Methods and compositions to treat myocardial conditions

ABSTRACT

Methods, devices, kits and compositions to treat a myocardial infarction. In one embodiment, the method includes the prevention of remodeling of the infarct zone of the ventricle. In other embodiments, the method includes the introduction of structurally reinforcing agents. In other embodiments, agents are introduced into a ventricle to increase compliance of the ventricle. In an alternative embodiment, the prevention of remodeling includes the prevention of thinning of the ventricular infarct zone. In another embodiment, the prevention of remodeling and thinning of the infarct zone involves the cross-linking of collagen and prevention of collagen slipping. In other embodiments, the structurally reinforcing agent may be accompanied by other therapeutic agents. These agents may include but are not limited to pro-fibroblastic and angiogenic agents.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of co-pending U.S. patent applicationSer. No. 12/632,612, filed Dec. 7, 2009, which is a divisional of U.S.patent application Ser. No. 10/414,767, filed Apr. 15, 2003 (now U.S.Pat. No. 7,641,643), and incorporated herein by reference.

FIELD

The treatment of myocardial infarction, and more particularly, in oneembodiment, the reinforcement of the infarct regional wall of a heartchamber and/or the inhibition the thinning of the infarct regional wallof a heart chamber.

BACKGROUND

Ischemic heart disease typically results from an imbalance between themyocardial blood flow and the metabolic demand of the myocardium.Progressive atherosclerosis with increasing occlusion of coronaryarteries leads to a reduction in coronary blood flow. Blood flow can befurther decreased by additional events such as changes in circulationthat lead to hypoperfusion, vasospasm or thrombosis.

Myocardial infarction accounts for approximately 20% of all deaths. Itis a major cause of sudden death in adults.

Myocardial Infarction (MI) is one form of heart disease that oftenresults from the sudden lack of supply of oxygen and other nutrients.The lack of blood supply is a result of closure of the coronary arterythat nourishes the particular part of the heart muscle. The cause ofthis event is generally caused by arteriosclerosis “hardening of thearteries” in coronary vessels.

Formerly, it was believed that an MI was caused from a slow processionof closure from for example 95% then to 100% but an MI can also be aresult of minor blockages where, for example, there is a rupture of thecholesterol plaque resulting in blood clotting within the artery. Thus,the flow of blood is blocked and downstream cellular damage occurs. Thisdamage can cause irregular rhythms that can be fatal, even though theremaining muscle is strong enough to pump a sufficient amount of blood.As a result of this insult to the heart tissue, scar tissue tends tonaturally form.

Even though relatively effective systemic drugs exist to treat MI suchas ACE-inhibitors and Beta-blockers, a significant portion of thepopulation that experiences a major MI ultimately develop heart failure.An important component in the progression to heart failure is remodelingof the heart due to mechanical forces resulting in uneven stress andstrain distribution in the left ventricle. Once an MI occurs remodelingof the heart begins. The principle components of the remodeling eventinclude myocyte death, edema and inflammation, followed by fibroblastinfiltration and collagen deposition, and finally scar formation. Theprinciple component of the scar is collagen. Since mature myocytes of anadult are not regenerated the infarct region experiences significantthinning Myocyte loss is the major etiologic factor of wall thinning andchamber dialation that may ultimately lead to progression of cardiacmyopathy. Myocyte death can and does occur. In other areas, remoteregions experience hypertrophy (thickening) resulting in an overallenlargement of the left ventricle. This is the end result of theremodeling cascade. These changes in the heart result in changes in thepatient's lifestyle and their ability to walk and to exercise. Thesechanges also correlate with physiological changes that result inincrease in blood pressure and worsening systolic and diastolicperformance.

FIGS. 1A-1C illustrates blood flow by longitudinal cross sectioning ofthe artery. FIG. 1A illustrates a normal unobstructed artery. FIG. 1Billustrates artery damage due to a tear or spasm. This figureillustrates a minor insult to the interior wall. FIG. 1C illustrates anartery with plaque build-up that reduces the blood flow demonstrated bythe blocked blood cell above the atherosclerotic mass. Fat andcholesterol build up at the site of damage. This mass can be detected bymethods currently available such as an, ECG, SPECT, MRI, angiogram.

FIGS. 2A-2B illustrate the progression of heart damage once the build-upof plaque induces an infarct to occur. The most common pathogenesis ofthis disease is occlusive intracoronary thrombus where a thrombus iscovering an ulcerated stenotic plaque. This causes approximately 90% oftransmural acute myocardial infarctions. Other possible triggers of anMI are vasospasms with or without coronary atherosclerosis and possibleassociation with platelet aggregation. Another possible trigger isembolisms from left-sided mural thrombosis, vegetative ensocarditis or aparadoxic embolism from the right side of the heart through a patentforamen ovale. FIG. 2A illustrates a site where blockage and restrictedblood flow can occur from any of the indicated causes. FIG. 2Billustrates the extensive damage to the left ventricle that can be aresult of the lack of oxygen and nutrient flow carried by the blood tothe inferior region left ventricle of the heart. This area will likelyundergo remodeling and eventually a scar will form and a non-functional(an area that does not contract) area will exist.

Significant atherosclerotic build-up can reduce the arterial lumen andreduce blood flow. Build-up is capable of rupturing resulting in a totalor partial occlusion of the artery. Complete coronary occlusion willlead to an acute MI. Thus the T-cells, platelets, fibrin and multipleother factors and cells are blocked from progression through the bloodstream and the result is an inadequate vascular supply as seen. Thisleads to myocyte death. Myocyte death, in addition to fibrosis in theform of collagen deposition, can lead to a compromised left ventricleand overload on the remaining myocytes. This process is furthercomplicated by compensation of the remaining myocytes that hypertrophy(enlarge). This can cause the left ventricle to enlarge and if the cyclecontinues can result in eventual heart failure.

The morphological appearance of the infracted heart tissue post M.I. canvary. A transmural infarct involves the entire thickness of the leftventricular wall from the endocardium to the epicardium. It may extendinto the anterior free wall and the posterior free wall. This damage mayinclude extensions into the right ventricular wall. A subendocardialinfarct may have multiple focal regions and necrosis area may beconfined to the inner one-third to one-half of the left ventricularwall. The evolutionary changes in a subendocardial infarct do not evolvethe same as in a transmural MI.

Over time post-MI morphological changes occur. The gross morphologicalchanges that occur over approximately a 7-week period are pallor of themyocardium that leads to some hyperemia then a yellowing starts to occurcentral to the damaged region. At approximately 15 days, the area ismostly yellow with soft vascular margins. This area eventually turnswhite from fibrosis. On a microscopic level, the initial examinationreveals wavy myocardial fibers. Coagulation and necrosis with loss ofcross striations occur followed by contraction bands, edema, hemorrhage,and neutrophilic infiltrate. Within 24-72 hours there is total loss ofnuclei and striations and heavy neutrophilic infiltrate. Then macrophageand mononuclear infiltration begin resulting in a fibrovascularresponse. Once this fibrovascular response occurs then prominentgranulation of the tissue follows. This ultimately leads to fibrosis anda scar is formed by about 7 weeks post MI.

FIGS. 3A-3B illustrate the occlusion of an artery that may lead to anMI. FIG. 3A illustrates the cross-section of a normal coronary arterywith unobstructed lumen 301. The normal arterial wall 302 is made up ofan intima layer 303, a media layer 304, and an adventitia layer 305.Within the arterial lumen, the intima is in direct contact with the flowof blood. This region is mostly made up of endothelial cells. The medialayer is mostly smooth muscle cells and extracellular matrix proteins.Finally, the aventitia layer is primarily made up of collagen, nerves,blood vessels and lymph vessels. FIG. 3B illustrates a coronary arterywith atherosclerosis. In this example, this artery is about 50 percentoccluded (only 50 percent of the arterial lumen is free of obstruction).Thus, the obstructed artery may lead to damage observed in a ventricleof an MI subject.

After an MI has occurred, three layers of tissue can be distinguished.The infarct region has (1) the region of significant necrosis/apoptosistissue (2) the border zone that consists of a large concentration ofapoptotic and necrotic tissue as well as viable tissue and (3) theunaffected region that consists of mainly viable tissue. In the borderzone the cells exist in an oxygen-deprived state due to the damage fromthe MI.

FIGS. 3C-3J illustrate the details of a post-MI remodeling of theventricle. The progression of heart failure after an MI is a result ofthe remodeling of the heart after the infarct. The remodeling processcauses infracted region of the heart to stretch and become thinnercausing the left ventricular diameter to increase. As the heartcontinues to remodel, the stresses on the heart increase. FIG. 3C, on acellular level, a normal myocardium is illustrated. FIG. 3C illustratesthe cross striations 306 and central nuclei 307 of a healthy myocytepopulation.

FIGS. 3D-3J depict the progression of the remodeling of the ventriclepost MI. FIG. 3D illustrates an early acute MI. Here, there areprominent pink contraction bands that are indicated by reference number308. FIG. 3E illustrates the increasing loss of striations and somecontraction bands. The nuclei in this illustration are incurringkaryolysis (A stage of cell death that involves fragmentation of a cellnucleus. The nucleus breaks down into small dark beads of damagedchromatin) 309. In addition, the neutrophils are infiltrating thedamaged myocardial region. FIG. 3F illustrates an acute MI. The loss ofnuclei and loss of cross striations are evident. There is extensivehemorrhaging on the infarct border 310. FIG. 3G illustrates theprominent necrosis and hemorrhaging 310, as well as the neutrophilicinfiltrate 311. Subsequently, a yellowish center is formed within thedamaged area with necrosis and inflammation surrounded by the hyperemicborder. After 3-5 days post-MI, the necrosis and inflammation areextensive. There is a possibility of rupture at this point. FIG. 3Hillustrates approximately one week after the MI with capillaries,fibroblasts and macrophages filled with haemosiderin (haemosiderin is along-term reserve (storage form) of iron in tissues) 312. In two tothree weeks granulation is the most prominent feature observed. FIG. 3Iillustrates extensive collagen deposition 313 seen after a couple ofweeks. Collagenous scarring occurs in subendocardial locations in remotemyocardial infarct regions. FIG. 3J illustrates the myocytes 314 afterseveral weeks of healing post MI. They are hypertrophied with large darknuclei 315 and interstitial fibrosis 316. These enlarged cellscontribute to the enlarged left ventricle.

A complication of an MI is an aneurysm that looks like a bulge in theleft ventricular wall. The aneurysm is made up of non-functional tissuethat is unable to contract. Therefore, the ejection and stroke volume ofthe heart are reduced. Additionally, parts of this mass can form a muralthrombus that can break off and embolize to the systemic circulation.

SUMMARY

Compositions and methods to treat myocardial infarction of the ventricleare described. In one embodiment, a composition is described that iscapable of reinforcing the ventricular wall and may be capable ofreleasing an agent to recruit the natural cell population in order tostabilize the region. In another embodiment, a method is described toincrease the compliance of a ventricle. A treatment agent is advancedthrough a delivery device to the infarct zone. In some embodiments, adelivery device is described to accurately deliver one or more treatmentagents. In some embodiments, the treatment agent is delivered via amultiple of small volumes to the region. These delivery methods may useimaging of the ventricular wall to guide the deposition of the treatmentagent to the site of the infarct zone such as deposition of thegel-forming agents. In other embodiments, treatment agents may induceangiogenesis.

In another embodiment, a method includes the retention of and/orrecruitment of fibroblast cells to the infarct zone. In otherembodiments, a method includes an early time post-MI recruitment andsubsequent retention of fibroblast cells in the infarct zone.Therapeutic agents are delivered to the infarct zone such as growthfactors and pro-fibroblastic agents to recruit surrounding fibroblaststo the area. These agents may be delivered by microparticles harboringthese therapeutic agents or direct delivery of the therapeutic agents tothe infarct region. The naturally occurring fibroblasts that infiltratethe infarct region may be stimulated to proliferate in addition torecruiting new fibroblasts to the region. In other embodiments, thesefibroblasts may be encouraged to convert from a non-contractile cell toa muscular cell by delivering growth factors to the infarct region suchas transforming growth factor-β1. This retention of fibroblasts in theinfarct zone is suitable for reinforcing the region and preventing thethinning process of the ventricular wall.

Other embodiments directed to the prevention of thinning of the infarctregion of the ventricle wall are included. Treatment agents that arecapable of cross-linking the existing collagen in the infarct region aredescribed. The cross-linked collagen would form a structurallyreinforcing wall in the infarct region to bulk-up the infarct zone andreduce the effects of thinning.

In another embodiment, a method includes multi-component treatments ofthe infarct zone. One multi-component method includes the formation of ascaffold to facilitate the attachment of fibroblasts and to delivergrowth factors and other treatment agents. In addition, the in-growth ofnew capillaries is encouraged by the sustained release of angiogenicfactors by the microparticles that form the scaffold. The treatmentagents may be released for up to two months period. This technique wouldoffer maximum benefit for the regeneration of viable tissue.

In another embodiment, a different multi-component treatment of theinfarct zone introduces a scaffold system that provides a matrix tofacilitate cell growth and inhibit the remodeling event post-MI. Inaddition the treatment includes a perfluorinated compound that enhancesthe re-oxygenation of the tissue.

In another embodiment, the blood that rapidly infiltrates the infarctregion may be clotted. The clotting of the blood by various agents, forexample fibrin glue, would result in a mass. This clot would alsoprovide reinforcement of the wall and prevention of the thinningprocess. The intervention of the thinning process by clotting must occurwithin four hours of the MI but would provide early structuralreinforcement of the infarct zone.

In another embodiment, a solution is delivered to a site in a ventricle.The solution contains an agent(s) capable of precipitating at a regionfor reinforcement of that region. Another solution contains one or moreagents that are delivered to a region in a ventricle and remain in thatregion while the supporting solution dissipates into surrounding tissue.

In one embodiment, the treatments proposed may occur at any time afteran infarction. In another embodiment, the treatments proposed may occurwithin seven weeks of an MI event (or prior to myocyte replacement). Inanother embodiment, the treatments proposed may occur within two weeksof an MI event.

In a further embodiment, a kit is disclosed. One example of such a kitis a kit including an injectable composition having the property offorming a gel once introduced to the treatment area. The gel may beformed due to one or more environmental changes or alternatively aresponse to one or more internal components.

BRIEF DESCRIPTION OF THE DRAWINGS

The methods and compositions are illustrated by way of example, and notlimitation, in the figure of the accompanying drawings in which:

FIG. 1A illustrates a longitudinally sectioned healthy artery and bloodflow therein.

FIG. 1B illustrates a longitudinally sectioned damaged artery due to atear or a spasm.

FIG. 1C illustrates a longitudinally sectioned occluded artery due tofat and cholesterol build up.

FIG. 2A illustrates plaque build up in an artery that may resultrestriction of blood and oxygen flow to the heart.

FIG. 2B illustrates the damage to the heart as a result of the plaguebuild-up in an artery that lead to an MI.

FIG. 3A illustrates a normal artery.

FIG. 3B illustrates an artery with arteriosclerosis (50 percentblockage) that may lead to an MI.

FIG. 3C illustrates normal myocardium.

FIG. 3D illustrates an example of myocardium of an early acutemyocardial infarction.

FIG. 3E illustrates an example of myocardium of an early myocardialinfarction whereby a myocardium demonstrates increasing loss of crossstriations.

FIG. 3F illustrates an example of myocardium of an acute myocardialinfarction and the loss of striations and the nuclei.

FIG. 3G illustrates an example of myocardium of an acute myocardialinfarction resulting in neutrophilic infiltration and necrosis.

FIG. 3H illustrates an example of the myocardium of an acute myocardialinfarction approximately one week after a myocardial infarctionoccurred. The capillaries, fibroblasts and macrophages fill withhemosidem.

FIG. 3I illustrates an example of the myocardium a couple of weeks aftera myocardial infarction. A lot of collagen has been deposited at thesite of damage.

FIG. 3J illustrates myocardium several weeks after a myocardialinfarction. Many surviving myocytes appear hypertrophic and their nucleiare dark in color. Interstitial fibrosis is also observed.

FIG. 4 illustrates various ways to restructure remodeling of the infarctregion via retention and recruitment of fibroblasts and delivering aswellable reinforcing material and/or introduce additional tropoelastinto the infarct region.

FIGS. 5A-5E illustrates the introduction of a pro-fibroblastic agent toan infarct zone and the formation of structural scaffolding

FIG. 6 illustrates a multi-component method for structurally reinforcingan infarct region.

FIG. 7 illustrates a multi-component method for structurally reinforcingan infarct region and/or facilitating oxygenation of an infarct region.

FIG. 8 illustrates a general structure of the first and of the secondcomponent of FIG. 7.

FIGS. 9A-9F illustrate introduction of three components to the infarctregion to treat an MI.

FIG. 10 illustrates an ester bond formed by at least two of thecomponents of embodiments illustrated in FIG. 7 and FIG. 8.

FIGS. 11A-11F illustrates introduction of structural reinforcement inthe form of swellable microparticles to an infarct zone.

FIG. 12 illustrates a flowchart of the several possible structuralreinforcing agents that may be introduced to an infarct region.

FIG. 13 illustrates an expansion of FIG. 12 1240 disclosing possibledual component systems.

FIG. 14 illustrates introduction and action of the methods illustratedin the flowchart of FIG. 13 in an infarct region.

FIG. 15 illustrates two possible methods to structurally reinforce aninfarct zone by bulking up a region.

FIG. 16 illustrates examples of bulking agents that may structurallyreinforce an infarct region.

FIG. 17 illustrates stabilizing the collagen in an infarct zone bycross-linking.

FIG. 18 illustrates various agents that may cross-link the collagen inan infarct region.

FIG. 19 illustrates various embodiments to clot the blood in an infarctregion post MI.

FIG. 20 illustrates various methods to reinforce an infarct region usinglight sensitive components.

FIGS. 21A-21E illustrates a cross-sectional view of introduction of anembodiment using a photo-polymerizable component of FIG. 20 to aninfarct region.

FIG. 22A illustrates a longitudinal view of a catheter device that has alight source and at least one component lumen.

FIG. 22B illustrates a cross-sectional view of a catheter device thathas a light source and at least one component lumen.

FIG. 23 illustrates one example of a multi-component method to reinforcethe infarct region and/or re-oxygenate the infarct region.

FIG. 24A illustrates a longitudinal view of a catheter device that hastwo delivery ports and a control mechanism to deliver one componentprior the second component.

FIG. 24B illustrates a front view of the distal end of a catheter devicewith two delivery ports.

FIG. 24C illustrates the distal end of a catheter device where onedelivery port may be extended while the second port may be confined tothe housing of the catheter.

FIGS. 25A-25D illustrates the introduction of two separate componentsinto an infarct region of the ventricle and formation of a structurallyreinforcing composition at the infarct region using a catheter withretractable dual delivery ports.

FIG. 26 illustrates the introduction of one component through a vein andthe second through an artery using the catheter with retractable dualdelivery ports.

DEFINITIONS

“a container” A receptacle, such as a carton, can, vial, tube, bottle,or jar, in which material is held or carried.

“cardiomyocyte-like”—a cell(s) capable of converting to acardiomyocyte(s) or a cell or components capable of functioning like acardiomyocyte.

“polymer-forming”—any agent or agents capable of forming a gelatinousmaterial either alone or in combination.

“delivery device”—an apparatus or system capable of depositing asolution, powder, concentrate, a single reagent and/or multiplereagents.

“pro-fibroblastic” agent—one or more compounds capable of retaining,inducing proliferation of and/or recruiting fibroblasts cells.

“compliance”—The ability of a blood vessel or a cardiac chamber tochange its volume in response to changes in pressure has importantphysiological implications. In physical terms, the relationship betweena change in volume (D V) and a change in pressure (D P) is termedcompliance (C), where C=DeltaV/Delta P. Compliance, therefore, isrelated to the ease by which a given change in pressure causes a changein volume. In biological tissues, the relationship between DV and DP isnot linear. Compliance is the slope of the line relating volume andpressure that decreases at higher volumes and pressures. Another way toview this is that the “stiffness” of the chamber or vessel wallincreases at higher volumes and pressures. Changes in compliance haveimportant physiological effects in cardiac chambers and blood vessels.

DETAILED DESCRIPTION

In the following section, several embodiments of, for example,processes, compositions, devices and methods are described in order tothoroughly detail various embodiments. It will be obvious though, to oneskilled in the art that practicing the various embodiments does notrequire the employment of all or even some of the specific detailsoutlined herein. In some cases, well known methods or components havenot been included in the description in order to prevent unnecessarilymasking various embodiments.

Methods and compositions to treat a ventricle after a myocardialinfarction (MI) are disclosed. In one embodiment, the infarct region orthe area of the ventricle containing the infarct injury may be treatedalone or in combination with other treatments. One benefit to suchtreatment is that the region of injury may be targeted with little or noaffect on the outlying healthy heart tissue. In addition, anotherbenefit of such treatment is that the treatment may prevent the loss offunctionality of a region of injury due to the normal remodeling andscar forming procedure to mend an infarct region. Another benefit may bethat the treatment may increase the compliance of the ventricle. Stillanother benefit is the reduction in thinning of a ventricular wall of aninfarct zone. In the following description, structural reinforcement ofthe infarct region of the ventricle is described. Since most myocardialinfarctions occur in the left ventricle most descriptions will bedirected towards left ventricle repair. But, it is appreciated thattreatment of the right ventricle may be achieved in a similar manner.

If the remodeling of the infarct region could be modified prior to scarformation and ultimate thinning of the ventricular wall, functionaltissue may be rescued. The inhibition of scar formation and guidedregeneration of viable cells would lead to increased wall strength anddecreased collagen deposition, instead of thinning and hypertrophiedmyocytes. Further, decreasing the probability of wall thinning andfortifying the influx of structural components such as fibroblasts mightbe beneficial and preferred over the current treatment of an MI, namelycontinual exposure to systemic drugs to treat the symptoms and not thedisease. Another benefit may be that any one of the treatments hereinmay result in an increase in compliance of the ventricle. Thus, any oneor more combinations of these treatments may provide a potential forhealing the infarct region and prevention of further complications.

In other embodiments, a kit (e.g., a pre-manufactured package) isdisclosed. A suitable kit includes at least one agent and a lumen tohouse the agent. The agent has a property that may increase the modulus(tensile strength, “stiffness”) of elasticity of the infarct region,increase compliance of the ventricle and/or prevent or reduce thinningcaused by remodeling. The kit may be suitable, in one example, in themethods described.

Mapping of the Heart

In each of the methods described herein, it is appreciated that specificareas of the heart may be targeted for application of any of theincorporated methods, thus there are techniques previously describedthat may be used for targeting the infarct region. One example oftargeting a specific region such as an infarct zone uses a techniqueknown as mapping the heart (U.S. Pat. No. 6,447,504). The data areacquired by using one or more catheters that are advanced into theheart. These catheters usually have electrical and location sensors intheir distal tips. Some of the catheters have multiple electrodes on athree-dimensional structure and others have multiple electrodesdistributed over a surface area. One example of the later catheter maybe a sensor electrode distributed on a series of circumferences of thedistal end portion, lying in planes spaced from each other. Thesetechniques provide methods to characterize the condition of the heart insome situations using electrical potentials in the heart tissue as wellas using electromechanical mapping, ultrasonic mapping to map the viableand the non-viable regions of the heart for example the left ventricleand the infarct zone. In addition, the ultrasound waves may be used todetermine the thickness of the heart tissue in the vicinity of the probefor example, sensing the characteristic of the heart tissue by analyzingthe ultrasound signals to determine the depth of the channels. Anothermethod known as viability mapping (for example Spect, MRI, PET) may alsobe used. Viability mapping may be used to identify areas of the heartthat are ischemic but still viable as well as area that have lost theirviability due to infarction. These maps are based onelectrophysiological data that indicate the flow of activation signalsthrough the heart tissue. In addition, the data may be biomedical and/ormechanical data for example, variations in the thickness of the heartwall between systolic and diastolic stages of the heart cycle. The datathat is used to analyze the heart by mapping may also be a combinationof electrophysiological and biomedical data in order to more accuratelylocate and target the infarct region. In absence of viability mappingdevices, it is appreciated that the location of the infarction may bealso assessed through LV angiography or echo, where location of theakinetic or hypokinetic region may be identified.

Delivery Systems

Any one or more catheters may be used to deliver the any one or multiplecomponents of the embodiments to the infarct region area. Severalcatheters have been designed in order to precisely deliver agents to adamaged region within the heart for example an infarct region. Severalof these catheters have been described (U.S. Pat. Nos. 6,102,926;6,120,520; 6,251,104; 6,309,370; 6,432,119; 6,485,481). The deliverydevice may include an apparatus for intracardiac drug administration,including a sensor for positioning within the heart, a delivery deviceto administer the desired agent and amount at the site of the positionsensor. The apparatus may include, for example, a catheter body capableof traversing a blood vessel and a dilatable balloon assembly coupled tothe catheter body comprising a balloon having a proximal wall. A needlemay be disposed within the catheter body and includes a lumen havingdimensions suitable for a needle to be advanced there through. Theneedle body includes an end coupled to the proximal wall of the balloon.The apparatus also includes an imaging body disposed within the catheterbody and including a lumen having a dimension suitable for a portion ofan imaging device to be advanced there through. The apparatus mayfurther include a portion of an imaging device disposed within theimaging body adapted to generate imaging signal of the infarct regionwithin the ventricle. The apparatus may be suitable for accuratelyintroducing a treatment agent at a desired treatment site.

In another embodiment a needle catheter used to deliver the agent to theventricle for example, the infarct region, may be configured to includea feedback sensor for mapping the penetration depth and location of theneedle insertion. The use of a feedback sensor provides the advantage ofaccurately targeting the injection location. Depending on the type ofagent administered, the target location for delivering the agent mayvary. For example, one agent may require multiple small injectionswithin an infarct region where no two injections penetrate the samesite.

In other embodiments, the catheter assembly may include a maneuverableinstrument. This catheter assembly includes a flexible assembly. Thecatheter assembly may be deflectable and includes a first catheter, asecond catheter, and a third catheter. The second catheter fitscoaxially within the first catheter. At least one of the first catheterand the second catheter include a deflectable portion to allowdeflection of that catheter from a first position to a second position,and the other of the first catheter and second catheter includes aportion which is preshaped (e.g. an angled portion formed by twosegments of the angled portion). The third catheter has a sheath and amedical instrument positioned within the sheath. The third catheter fitscoaxially within the second catheter. In another embodiment, astabilizer, such as a donut shaped balloon, is coupled to a distalportion of the third catheter. Each catheter is free to movelongitudinally and radially relative to the other catheters. Thecatheter assembly may be used but not limited to the local delivery ofbioagents, such as cells used for cell therapy, one or more growthfactors for fibroblast retention, or vectors containing genes for genetherapy, to the left ventricle. In one embodiment, the catheter assemblydescribed may be used in delivering cell therapy for heart failure or totreat one or more portions of the heart that are ischemic. The catheterassembly uses coaxially telescoping catheters at least one or more beingdeflectable, to position a medical instrument at different targetlocations within a body organ such as the left ventricle. The catheterassembly may be flexible enough to bend according to the contours of thebody organ. The catheter assembly may be flexible in that the catheterassembly may achieve a set angle according to what the medical procedurerequires. The catheter assembly will not only allow some flexibility inangle changes, the catheter assembly moves in a three coordinate systemallowing an operator greater control over the catheter assembly'smovement portion of the second catheter, allowing for the distal tip ofthe third catheter to be selectively and controllably placed at amultitude of positions. It will be appreciated that the deflectableportion may alternatively be on the second catheter and the preshapedportion may be on the first catheter.

In a further embodiment, an apparatus is disclosed. In one embodiment,the apparatus includes a first annular member having a first lumendisposed about a length of the first annular member, and a secondannular member coupled to the first annular member having a second lumendisposed about a length of the second annular member, whereincollectively the first annular member and the second annular member havea diameter suitable for placement at a treatment site within a mammalianbody. Representatively, distal ends of the first annular member and thesecond annular member are positioned with respect to one another toallow a combining of treatment agents introduced through each of thefirst annular member and the second annular member to allow a combiningof treatment agents at the treatment site. Such an apparatus isparticularly suitable for delivering a multi-component gel material(e.g., individual components through respective annular members thatforms a bioerodible gel within an infarct region of a ventricle).

In the embodiments described herein, a substance delivery device and amethod for delivering a substance are disclosed. The delivery device andmethod described are particularly suitable, but not limited to, localdrug delivery in which a treatment agent composition (possibly includingmultiple-treatment agents and/or a sustained-release composition) isintroduced via needle delivery to a treatment site within a mammalianhost. A kit of a treatment agent composition is also described. Onesuitable application for a delivery device is that of a catheter device,including a needle delivery system. Suitable therapies include, but arenot limited to, delivery of drugs for the treatment of arterialrestenosis, therapeutic angiogenesis, or cancer treatment drugs/agents.

In other embodiments, larger doses of treatment agent may be consideredfor example about 2 mls to about 250 mls that may require any one ormore of the delivery devices such as intra-venous retro infusion,intra-arterial infusion and needle catheter systems (Invigor) as well assubxyphoid approaches.

Various apparati (devices) and methods described herein can be used as astand-alone injection needle/catheter during a surgical procedure suchas an open heart surgery (e.g., Coronary Bypass Graft (CABG)) procedurein which areas of the heart may be treated with, for example, growthfactors, for affecting therapeutic angiogenesis, or incorporated into acatheter-based system to access locations that are commonly used inpercutaneous translumena. 1 coronary artery (PTCA) procedures. Theapparati (devices) and methods may similarly be used in other surgicalprocedures such as cancer-related procedures (e.g., brain, abdomen, orcolon cancer procedures or surgeries). Additionally, various apparati(devices) and methods described herein can be used in conjunction withvarious catheter-related or endoscopy procedures that generally requireminimal invasiveness to deliver a specific drug or growth factor intotissue. Examples of such procedures include, but are not limited to,orthoscopic surgery for joints (e.g., knee), laparoscopic surgery forthe abdomen, and thoracoscopic procedures related to chest injuries ortreatments.

One concern of introducing any treatment agent composition, whetheradjacent a blood vessel to affect therapeutic angiogenesis, adjacent toa tumor to inhibit tumor growth, or to induce or stimulate collagengrowth in orthoscopic procedures, is that the composition remain (atleast partially) at the treatment site for a desired treatment duration(or a portion of the treatment duration). In this manner, an accuratedosage may be placed at a treatment site with reduced concern that thetreatment agent will disperse, perhaps with serious consequences. In oneembodiment, a composition and technique for retaining a treatment agentat a treatment site (injection site) is described. In one embodiment, atreatment agent and a bioerodible gel or non-bioerodible gel or particlemay be introduced at a treat site (e.g., an injection site). The gel orparticle(s) may be introduced prior to, after, or simultaneously withthe treatment agent. In one preferred embodiment, the gel or particle(s)acts to retain the treatment agent at the treatment site by,representatively, sealing the treatment site or sealing the treatmentagent at the treatment site. The use of a gel or particle(s) with atreatment agent can reduce the amount of treatment agent backflow fromthe injection site as well as reduce the load requirement of thetreatment agent at the treatment site. For example, a bioerodibleproduct such as a gel or particle may decrease the local pressurethereby further resulting in backflow reduction. A non-bioerodibleproduct may also decrease the local pressure to reduce the backflow in amore permanent fashion and at the same time may also lead to an increasein compliance.

Using the above-mentioned techniques, an imaging modality may be addedsuch as a contrast-assisted fluorescent scope that permits acardiologist to observe the placement of the catheter tip or otherinstrument within the heart chamber. The contrast-assisted fluoroscopyutilizes a contrast agent that may be injected into heart chamber andthen the area viewed under examination by a scope, thus the topographyof the region is more easily observed and may be more easily treated(U.S. Pat. Nos. 6,385,476 and 6,368,285). Suitable imaging techniquesinclude, but are not limited to, ultrasonic imaging, optical imaging,and magnetic resonance imaging for example Echo, ECG, SPECT, MRI,Angiogram. Therefore, mapping of the heart is one technique that may beused in combination with the techniques proposed in the followingembodiments. In one embodiment, an echo angiograph may be performed toconfirm the occurrence and the location of the infarct region. Inanother embodiment, a Cat Scan may be performed to confirm an MI hasoccurred and the location of the infarct region. In another embodimentan EKG may be performed to identify the occurrence and location of aninfarct.

In another embodiment, a method may include introducing a treatmentagent in a sustained release composition. The preferred period forsustained release of one or more agents is for a period of one to twelveweeks, preferably two to eight weeks. Methods for local delivery ofsustained release agents include but are not limited to percutaneousdevices for example intraventricular (coronary) or intravascular(coronary and peripheral) devices.

A. Fibroblast Retention and Recruiting Agents

1. Agents

FIG. 4 describes one embodiment of a method to treat an infarct regionof a left ventricle. This is an illustrative diagram only and any of thetreatments may be used in parallel (e.g., at the same time) orsequentially or in any treatment combination. According to the methodillustrated in FIG. 4, a myocardial infarction may be detected by animaging process for example magnetic resonance imaging, optical imagingor ultrasonic imaging for example Echo ECG, spect, MRI, angiogram 410.Next, the area of the left ventricle is reinforced 410 by retention orrecruitment of surrounding fibroblasts cells 420. In FIG. 4 one optionto encourage the fibroblast occupancy of the infarct zone includes theuse of swellable material 430 delivered to the infarct zone. Anothermethod, summarized in FIG. 4 440 to encourage the occupancy offibroblasts to the infarct zone includes the delivery of tropo-elastinto the site. It has been demonstrated that injections of fibroblastsinto a scar region may improve the structural integrity of a terminallyinjured heart in a rabbit model see (Hutcheson et al “Comparison ofbenefits on myocardial performance of cellular cardiomyoplasty withskeletal myoblasts and fibroblasts” Cell Transplant 2000 9(3) 359-68).Since the fibroblasts naturally infiltrate the scar during the healingprocess, it would be beneficial to attract these cells in largernumbers, or to induce their proliferation in the infarct region suchthat fibroblasts are encouraged to remain in the region for a prolongedperiod or permanently remain in the region. In addition, a furtherbenefit of retaining fibroblasts in an infarct region may be to convertthe fibroblast phenotype such as influencing the conversion fromnon-contractile cell to a muscular cell. The conversion is promoted inthe presence of growth factors for example TGF-β1 (transforming growthfactor beta 1). Therefore, the infarct region may be treated with agentsthat encourage fibroblast retention and recruitment. Suitable treatmentagents that may modify or recruit fibroblasts include but are notlimited to, Angiotensin II, fibroblast growth factor (FGF basic andacidic), insulin growth factor (IGF), TGFβ in any of its isoforms,vascular endothelial growth factor (VEGF) in any of its isoforms, tumornecrosis factor-alpha (TGF-α), platelet-derived growth factor-BB(PDGF-BB), angiogenin, angiopoietin-1, Del-1, follistatin, granulocytecolony-stimulating factor (G-CSF), pleiotrophin (PTN), proliferin,transforming growth factor-alpha (TGF-α), vascular permeability factor(VPF), and LIH (leukemia inhibitory factor) genes that encode theseproteins, transfected cells carrying the genes of these proteins, smallmolecules and pro-proteins that also contain these recruitingproperties.

In one embodiment, basic fibroblast growth factor may be introduced tothe infarct region by at least one of the methods described. In oneembodiment, any of the described agents may be introduced in one or moredoses in a volume of about 1 μl to 1 ml. In another embodiment, any ofthe described agents may be introduced in one or more doses in a volumeof about 1 μl to 300 μl. In another embodiment, any of the describedagents may be introduced in one or more doses in a volume of about 1 μlto 100 μl. In a preferred embodiment, the any of the described agentsmay be introduced in one or more doses in a volume of about 1 μl to 50μl.

In alternate embodiments, the treatment volume may be larger (e.g.,intravenous pressure perfusion (IV) route). These volumes may range fromabout 2 mls to about 250 mls. Alternatively, these volumes may rangefrom about 2 mls to about 100 mls. In other embodiments, these volumesmay range from about 2 mls to about 30 mls.

2. Sequence of Treatment

FIG. 4 illustrates a flow chart of a process for treating MI byretaining and recruiting fibroblasts. FIGS. 5A-5E illustrates theintroduction and action of fibroblast retention and recruitment.Detection of acute myocardial necrosis may be performed using an ECG(electocardiogram) or by a more modern technology. For example, onetechnology such as . . . ^(99m)Technetium-pyrophosphate or¹¹¹In-antimyosin antibody imaging has recently been approved by the Foodand Drug Administration. With both these two tracers, results areobtained only 24-48 hours after acute infarction and therefore, theclinical utility of these techniques have been limited. There is anothernew agent called ^(99m)Tc-glucurate that produces results within an hourafter acute myocardial infarction (Iskandrian, A S, Verani M S, NuclearCardiac Imaging Principles and Applications, Philadelphia, F. A. Davis1996). Once the MI is detected the exact location of the infarct may beidentified using a magnetic resonance imaging then the ventricle infarctregion may be treated by reinforcement 501. An agent 520 (for exampletropoelastin) is introduced to the infarct region 510. One way the agentmay be introduced to the area is percutaneously, with the use of acatheter. A distal end of the catheter is advanced to the infarct zone530, 540, or 550 and the agent 520 is released. Then the fibroblasts 560are recruited to the site or retained 570. FIG. 5E illustrates thefibroblast reinforcement of the infarct area.

3. Description of Several Possible Treatment Agent(s) and Deliveries.

a. Tropoelastin.

FIGS. 5A-5E describes the combination of promoting fibroblast retentionand migration into the infarct region with the addition of for exampletropoelastin 520. Elastin is a highly pliable extracellular protein. Invivo, it is usually in a cross-linked insoluble state. A linearuncross-linked soluble precursor is available that is referred to astropoelastin. Tropoelastin 520 can be made by recombinant methods and iscommercially available. Tropoelastin is an approximately 70-kDa proteinconsisting of alternating hydrophobic regions, responsible forelasticity, and cross-linking domains. Additionally, it ends with ahydrophilic carboxy-terminal sequence containing its only twocysteine-residues. Tropoelastin is a protein that is prominent in theskin of an infant and as one matures less and less of this protein ismade. Tropoelastin is sometimes used as an important marker of someheart conditions such as MI since it is released into the bloodstreamfollowing heart injury. The production of recombinant tropoelastin inbacterial systems has greatly simplified the availability oftropoelastin. In addition, it provides a valuable means for obtaininghuman tropoelastin. Purification from human aortas was greatlysimplified compared with tissue extraction methods but relatively lowyields were obtained. The purification from the aortas posed thepotential for degradation of the polypeptide. Recently, humantropoelastin cDNA has also been expressed in bacteria as a fusion withinfluenza NS1 protein (Indik, Z., Abrams, W. R., Kucich, U., Gibson, C.W., Mecham, R. P. and Rosenbloom, J. (1990) Production of recombinanthuman tropoelastin: characterization and demonstration of immunologicand chemotactic activity Arch. Biochem. Biophys. 280, 80-86). Thisisoform of tropoelastin, containing exon 26A and the signal peptide, wasthe first form of human tropoelastin to be obtained for study. In viewof tropoelastin's extreme amino acid usage, a synthetic humantropoelastin gene has been constructed containing codons designed tooptimize expression in E. coli (Martin, S. L., Vrhovski, B. and Weiss,A. S. (1995) Total synthesis and expression in Escherichia coli of agene encoding human tropoelastin Gene 154, 159-166). This synthetic geneis expressed at high levels in soluble form both as a fusion withglutathione S-transferase and directly, as the mature polypeptide.Alternatively, a simplified purification scheme using alcoholsolubilization and eliminating the need for cyanogen bromide (CNBr)treatment resulted in significantly higher yields. Therefore, purifiedor genetically engineered tropoelastin is available. Recombinant formsof tropoelastin have proved to be viable alternatives to tissue-derivedtropoelastin. Recombinant tropoelastin reacts with elastin antibodies,is a chemotactic agent, demonstrates coacervation ability and has thesome similar characteristics to naturally occurring tropoelastin (i.e.circular dichroism).

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 100 μl. In a preferred embodiment, any of the describedagents may be introduced in one or more doses in a volume of about 1 μlto about 50 μl.

b. Microparticles and Growth Factors Delivery.

One embodiment of a composition suitable for the described methodincludes the use of a bioerodible microparticle harboring one or more ofthe aforementioned growth factors. The bioerodible microparticle mayconsist of a bioerodible polymer such as poly(lactide-co-glycolide). Thecomposition of the bioerodible polymer is controlled to release thegrowth factor over a period of 1-2 weeks. It was previously demonstratedthat biodegradable microparticles for example,poly(lactide-co-glycolide) were capable of controlled release of anoligonucleotide. These microparticles were prepared by the multipleemulsion-solvent evaporation technique. In order to increase the uptakeof the oligonucleotide into the microparticles it was accompanied bypolyethylenimine (PEI). The PEI also tended to make the microparticlesmore porous thus facilitating the delivery of the oligonucleotide out ofthe particles. See (De Rosa et al. Biodegradable microparticles for thecontrolled delivery of oligonucleotides,” Int. J Pharm 2002 Aug. 21; 242(1-2):225). In one preferred embodiment of a composition, thebioerodible microparticle may be a PLGA polymer 50:50 with carboxylicacid end groups. PLGA is a base polymer often used for controlledrelease of drugs and medical implant materials (i.e. anti-cancer drugssuch as anti-prostate cancer agents). Two common delivery forms forcontrolled release include a microcapsule and a microparticle (e.g., amicrosphere). The polymer and the agent are combined and usually heatedto form the microparticle prior to delivery to the site of interest(Mitsui Chemicals, Inc). As the microparticles erode 560 a porousnetwork of the microparticle composition is formed 570 in the infarctregion resulting in a matrix with a controlled pore size 580. As theporous network is formed at least one angiogenic and/or pro-fibroblasticfactor may be released encouraging the in-growth of new capillaries. Oneembodiment, the bioerodible polymer harbors the growth factor TGF-β1. Inone embodiment, the PLGA polymer 50:50 with carboxylic acid end groupsharbors TGF-β1 for slow release. It is preferred that each microparticlemay release at least 20 percent of its contents and more preferablyaround 90 percent of its contents. In one embodiment, the microparticleharboring at least one angiogenic and/or pro-fibroblastic agent willdegrade slowly over time releasing the factor or release the factorimmediately upon contact with the infarct area in order to rapidlyrecruit fibroblasts to the site. In another embodiment, themicroparticles may be a combination of controlled-release microparticlesand immediate release microparticles. A preferred rate of deposition ofthe delivered factor will vary depending on the condition of the subjectundergoing treatment.

Another embodiment of a composition suitable for the described methodincludes the use of non-bioerodible microparticles that may harbor oneor more of the aforementioned growth factors. The growth factors may bereleased from the microparticle by controlled-release or rapid release.The microparticles may be placed directly in the infarct region. Bydirectly placing the particles in the infarct they may also provide bulkfor the region for reinforcement. The non-bioerodible microparticle mayconsist of a non-bioerodible polymer such as an acrylic basedmicrosphere for example a tris acryl microsphere (provided by BiosphereMedical). In one embodiment, non-bioerodible microparticles may be usedalone or in combination with an agent to increase compliance of aventricle. In another embodiment, non-bioerodible microparticles may beused alone or in combination with an agent to recruit fibroblasts and/orstimulate fibroblast proliferation. In addition, non-bioerodiblemicroparticles may be used to increase compliance and recruitfibroblasts to an infarct region of a ventricle.

In one embodiment, the treatment agent compositions suitable forreinforcement of the infarct zone are rendered resistant to phagocytosisby inhibiting opsonin protein absorption to the composition of theparticles. In this regard, treatment agent compositions includingsustained release carriers include particles having an average diameterup to about 10 microns are considered. In other situations, the particlesize may range from about 1 mm to about 200 mm. The larger sizeparticles may be considered in certain cases to avoid macrophagefrustration and to avoid chronic inflammation in the treatment site.When needed, the particle size of up to 200 mm may be considered and maybe introduced via an intraventricular catheter or retrograde venouscatheter for any of the embodiments herein to avoid chronic inflammationdue to macrophage influx into the treatment site.

One method of inhibiting opsonization and subsequent rapid phagocytosisof treatment agents is to form a composition comprising a treatmentagent disposed with a carrier for example a sustained release carrierand to coat the carrier with an opsonin inhibitor. One suitableopsonin-inhibitor includes polyethylene glycol (PEG) that creates abrush-like steric barrier to opsonization. PEG may alternatively beblended into the polymer constituting the carrier, or incorporated intothe molecular architecture of the polymer constituting the carrier, as acopolymer, to render the carrier resistant to phagocytosis. Examples ofpreparing the opsonin-inhibited microparticles include the following.

For the encapsulation polymers, a blend of a polyalkylene glycol such aspolyethylene glycol (PEG), polypropylene 1,2-glycol or polypropylene1,3-glycol is co-dissolved with an encapsulating polymer in a commonorganic solvent during the carrier forming process. The percentage ofPEG in the PEG/encapsulating polymer blend is between five percent and60 percent by weight. Other hydrophilic polymers such as polyvinylpyrolidone, polyvinyl alcohol, or polyoxyethylene-polyoxypropylenecopolymers can be used in place of polyalkylene glycols, althoughpolyalkylene glycols and more specifically, polyethylene glycol isgenerally preferred.

Alternatively, a diblock or triblock copolymer of an encapsulatingpolymer such as poly(L-lactide), poly(D,L-lactide), orpoly(lactide-co-glycolide) with a polyalkylene glycol may be prepared.Diblocks can be prepared by: (i) reacting the encapsulating polymer witha monomethoxy polyakylene glycol such as PEG with one protected hydroxylgroup and one group capable of reacting with the encapsulating polymer,(ii) by polymerizing the encapsulating polymer on to the monomethoxypolyalkylene glycol such as PEG with one protected group and one groupcapable of reacting with the encapsulating polymer; or (iii) by reactingthe encapsulating polymer with a polyalkylene glycol such as PEG withamino functional termination. Triblocks can be prepared as describedabove using branched polyalkylene glycols with protection of groups thatare not to react. Opsonization resistant carriers(microparticles/nanoparticles) can also be prepared-using the techniquesdescribed above to form sustained-release carriers(microparticles/nanoparticles) with these copolymers.

A second way to inhibit opsonization is the biomimetic approach. Forexample, the external region of cell membrane, known as the“glycocalyx”, is dominated by glycoslylated molecules that preventnon-specific adhesion of other molecules and cells. Surfactant polymersconsisting of a flexible poly(vinyl amine) backbone randomly-dextran andalkanoyl (hexanoyl or lauroyl) side chains which constrain the polymerbackbone to lie parallel to the substrate. Hydrated dextran side chainsprotrude into the aqueous phase, creating a glycocalyx-like monolayercoating that suppresses plasma protein deposition on the foreign bodysurface. To mimic glycocalyx, glycocalyx-like molecules can be coated onthe carriers (e.g., nanoparticles or microparticles) or blended into apolymer constituting the carrier to render the treatment agent resistantto phagocytosis. An alternate biomimetic approach is to coat the carrierwith, or blend in phosphorylcholine, a synthetic mimetic ofphosphatidylcholine, into the polymer constituting the carrier.

For catheter delivery, a carrier comprising a treatment agent (e.g., thecomposition in the form of a nanoparticle or microparticle) may besuspended in a fluid for delivery through the needle, at a concentrationof about one percent to about 20 percent weight by volume. In oneembodiment, the loading of the treatment agent in a carrier is about 0.5percent to about 30 percent by weight of the composition.Co-encapsulated with protein or small molecule treatment agents could bestabilizers that prolong the biological half-life of the treatment agentin the carrier upon injection into tissue. Stabilizers may also be addedto impart stability to the treatment agent during encapsulation.Hydrophilic polymers such as PEG or biomimetic brush-like dextranstructures or phosphorylcholine are either coated on the surface or thecarrier, grafted on the surface of the carrier, blended into the polymerconstituting the carrier, or incorporated into the moleculararchitecture of the polymer constituting the carrier, so the carrier isresistant to phagocytosis upon injection into the target tissuelocation.

Any one or more catheters may be used to deliver the any one or multiplecomponents of the embodiments to the infarct region area. Severalcatheters have been designed in order to precisely deliver agents to adamaged region within the heart for example an infarct region. Severalof these catheters have been described (U.S. Pat. Nos. 6,309,370;6,432,119; 6,485,481). The delivery device may include an apparatus forintracardiac drug administration, including a sensor for positioningwithin the heart, a delivery device to administer the desired agent andamount at the site of the position sensor.

Angiogenesis

After an MI the infarct tissue as well as the border zone and the remotezone begin to remodel. The scar tissue forms in the infarct region asthe granulation is replaced with collagen, causing the scar to thin outand stretch. The perfusion in this region is typically 10% of thehealthy zone, decreasing the number of active capillaries. Increasingthe number of capillaries may lead to an increase in compliance of theventricle due to filling up with blood. Other benefits of increasingblood flow to the infracted region is to provide a route for circulatingstem cells to seed and proliferate in the infarct region. Angiogenesismay also lead to increased oxygenation for the surviving cellular isletswithin the infarct region, or to prime the infract region for subsequentcell transplantation for myocardial regeneration. In the border zone,surviving cells would also benefit from an increase in blood supplythrough an angiogenesis process. In the remote zone, where cardiac cellstend to hypertrophy and become surrounded with some interstitialfibrosis, the ability of cells to receive oxygen and therefore functionto full capacity are also compromised; thus, angiogenesis would bebeneficial in these regions as well. In one embodiment, angiogenesiswill be stimulated in any region of the heart—infarct, border or remoteis through delivery of angiogenesis-stimulating factors. Examples ofthese factors include but are not limited to isoforms of VEGF (e.g.,VEGF121), FGF (e.g., b-FGF), Del 1, HIF 1-alpha (hypoxia inducingfactor), PR39, MCP-1 (monocyte chemotractant protein), Nicotine, PDGF(platelet derived growth factor), IGF (Insulin Growth Factor), TGF alpha(Transforming Growth Factor), HGF (Hepatocyte growth factor), estrogens,Follistatin, Proliferin, Prostaglandin E1, E2, TNF-alpha (tumor necrosisfactor), II-8 (Interleukin 8), Hemotopoietic growth factors,erythropoietin, G-CSF (granulocyte colony-stimulating factors), PD-ECGF(platelet-derived endothelial growth factor), Angogenin. In otherembodiments, these factors may be in provided in a sustained releaseformulation as independent factor or in combination with other factorsor appropriate gene vectors with any of the gel or microparticlecomponents described in this application.

c. Microparticles and Angiogenic and Pro-Fibroblastic Agents.

The microparticles may be prepared as microparticles harboring anangiogenic and/or pro-fibroblastic agent. On the other hand, themicroparticles may be prepared and then the angiogenic and/orpro-fibroblastic agent introduced into the microparticle for example bydiffusion prior to introduction to the infarct region. In the laterexample, the microparticles might also be coated with the factor andupon introduction to the infarct region the factor immediately recruitsfibroblasts to the area. Additionally, the microparticle-factorcomposition might consist of any combination of the above-mentionedtreatments. In other embodiments, it may be necessary to add at leastone pharmaceutically acceptable inhibitor to the microparticles thatprevents decomposition of the angiogenic or pro-fibroblastic agent.

d. Microparticle Components.

FIG. 4 describes a method to structurally reinforce the infarct region.This method may be combined with any of the methods describingintroducing angiogenic and/or fibroblast-recruiting agents, for examplegrowth factors, to the infarct region to retain and/or promotefibroblast migration to this zone. Microparticles capable of taking upfluid will be introduced to the infarct region. Examples of thesemicroparticles include swellable non-biological or synthetic biologicalparticles. The microparticles are introduced to the infarct zone andbecome trapped in the tissue. The microparticles tend to immediatelystart to swell. The swollen microparticles remain lodged in the tissueand provide reinforcement to the ventricular wall and add thickness tothe thinning infarct region.

The dimensions of the infarct zone may determine the size range of themicroparticles and the number of microparticles introduced to theinfarct region. This will insure that the optimum post-hydratedmicroparticle mass is achieved. An embodiment relates to microparticlesthat are about 200 microns or less in diameter. In another embodimentthe microparticles may be about 20 microns or less in diameter. In apreferred embodiment, the particle size may be about 5-10 microns indiameter. Particles of about 20 microns or less may also include anopsonization inhibitor (previously discussed). The swellablemicroparticles may be a range of sizes introduced to the infarct region.In one embodiment, the swellable non-biological material may be ahydrogel microsphere material. These microparticles are availablecommercially (A.P. Pharma or BioSphere Medical). These microparticlesare resistant to non-specific absorption and are bio-stable.

In other embodiments, hydrogels may be used as a treatment for amyocardial infarction. Examples of hydrogel materials are high molecularweight polyacrylamide or highmolecular weight polyvinylpyrrolidone(PVP). Typically the monomer is supplied in these products containingdi-functional monomers such as di-vinyl benzene, ethylene glycoldimethylacrylate or bis-acrylamide acetate resulting in the formation ofa cross-linked network resistant to dissolution in an aqueousenvironment or to stimulate controlled magnitude angiogenic response.These components may be used to generate microspheres. Alternatively thedi-functional polymers may be used to synthesize a hydrogel microsphere.

In one embodiment of the invention the first component of a biosyntheticpolymeric gel may be (acrylamidomethyl) cellulose acetate propionate andthe second component may be a dithiol functional polyethylene glycolpolymer (such as sold by Shearwater Polymers). In another embodiment,the first component of a biosynthetic polymeric gel may be(acrylamidomethyl) cellulose acetate proprionate and the secondcomponent may be a reduced peptide sequence. In a further embodiment,the reduced peptide sequence could be biologically derived such as theamino acid sequence,glycine-cysteine-tyrosine-lysine-asparagine-arginine-asparticacid-cysteine-glycine. A dual bore needle system may deliver bothcomponents separately one at a time or simultaneously to an infarctzone. The thiol-group(s) of the thiol-containing component may undergonucleophillic addition to the acrylamide functional group of the firstcomponent. This forms the elastomeric structurally reinforcing gel.

In other embodiments, the delivery of a nonbiologic or synthetic gel maybe combined with angiogenic and/or fibroblast recruiting agentsutilizing microparticles capable of releasing the agents at a rateoptimal for fibroblast retention and migration in the infarct region.

In one embodiment, tropoelastin suspended in a solution, such as saline,is introduced to the infarct region for structural reinforcement of theventricular wall. Another embodiment includes the introduction oftropoelastin suspended in saline in the presence of copper ions. Anotherembodiment includes the introduction of tropoelastin in the presence ofa converting enzyme. Another embodiment includes the introduction oftropoelastin in the presence of lysyl oxidase. Once introduced to theinfarct zone, the solution forms elastin by cross-linking via a lysineresidue oxidation. The cross-linked elastin remains in the infarctregion to fortify the tissue and enhance the modulus (wallstrength/elongation=modulus) of elasticity.

4. Methods for Introduction and Action.

FIGS. 5A-5E illustrates the introduction and action of pro-fibroblasticagents to the infarct region to recruit fibroblast cell growth. Thepro-fibroblastic agent may be introduced to the site 500 by a minimallyinvasive procedure 510. The solution may be injected in the infarct zoneduring an open chest procedure 520. The introduction of thepro-fibroblastic agent(s) includes one of the following procedures:sub-xiphoid and percutaneously 530. The mode of introduction of thepro-fibroblastic agent(s) by a percutaneous injection includes one ofthe following consisting of an intraventricular (coronary) catheter, atransvascular needle catheter, IC infusion and retrograde venousperfusion. One percutaneous route for a catheter is via a femoral arterytraversing through and then across the aortic arch into the leftventricle. Imaging techniques can guide the catheter to the infarctregion. The infarct region for example may be distinguished from healthytissue using MRI techniques. A catheter having imported the MRI data maythen be guided directly to the infarct region. Once the agent 540 isdistributed through out the infarct region 510, the fibroblasts 560 maybe attracted to the area by chemotactic responses. The fibroblast cellsthat infiltrate the area may proliferate in the area. Once thefibroblasts proliferate they form a reinforcing mass to the region andstrengthen the damaged site 510. The fibroblast in this aspect of thepresent invention may act as a structurally reinforcing agent in theinfarct zone 570. These cells add bulk to the area and replace thedegraded myocytes that normally lead to a thinning of the infarctregional wall. In turn, the viable fibroblast cells release factors thatmay recruit other cells into the area for further reinforcement of theinfarct zone.

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to about 100 μl. In a preferred embodiment, the any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to about 50 μl. If an agent is introduced via an IV or an ICroute the volumes may range from about 1 ml to about 500 ml.

Any one or more catheters may be used to deliver the any one or multiplecomponents of the embodiments to the infarct region area. Severalcatheters have been designed in order to precisely deliver agents to adamaged region within the heart for example an infarct region. Severalof these catheters have been described (U.S. Pat. Nos. 6,309,370;6,432,119; 6,485,481). The delivery device may include an apparatus forintracardiac drug administration, including a sensor for positioningwithin the heart, a delivery device to administer the desired agent andamount at the site of the position sensor.

B. Multiple Component Systems for Infarct Reconstruction.

Component 1:

To prevent heart failure, it has been proposed that cardiomyocytes canbe directly introduced into the infarct region to restore cardiacfunction cells of various origins, including embryonic and adult stemcells. The viability of tissue engineering for a myocardial infarct zonerequires that oxygen and nutrient supplies are readily available, aswell as a mode for removal of waste products from cell metabolism. Thecells in these areas also need a supporting structure for adherence. Thebioerodible gel with angiogenic and/or fibroblast recruiting agentspreviously discussed provides this later supporting structure. In theliterature, it is known that the introduction of scaffolding with a boresize of less than 10 microns leads to a tightly fibrotic encapsulatedscaffold with poor capillary in-growth. On the other hand asdemonstrated in FIGS. 6 and 9, if the scaffolding pore diameter isaround 20 microns, cellular encapsulation of the scaffold system is wellperfused with capillary in-growth leading to fibrotic poor cellular richregion. One embodiment includes scaffolding that is introduced to theinfarct zone 610, 910 and acts as a mechanical reinforcement. The forceis distributed more evenly 990 at the infarct region and ventricularremodeling is prevented.

In one embodiment, separate components are included to provide a networksuch as described above. One example is described in FIG. 6. Amulti-component composition includes the first component including thepreviously illustrated bioerodible matrix or scaffolding 630, 990. Inthis particular composition, the matrix (first component) provides aporous scaffolding to enhance capillary in-growth. The microparticles ofthe first component may be approximately 20 microns. In anotherembodiment, the first component of the composition may be introduced ina minimally invasive procedure 960 such as percutaneously. A distal endof the catheter is advanced to the infarct zone 910 and the bioerodiblemicroparticles 920 are released. In a further embodiment, the firstcomponent of the composition may be introduced via an intra-ventricularneedle device 930 to the infarct region. In a further embodiment, anintra-ventricular needle device including introducing multipleinjections to the infarct region may introduce the first component ofthe composition. The first component may serve in one aspect as a domainto promote cell growth. In addition, porosity may be controlled thatleads to capillary in-growth. The first component 920 may be abioerodible microparticle with growth factor and angiogenic potential.The factor or other agent may release over a 1-2 week period. Oneembodiment may be that the first component includes PLGA 50:50(previously described) with carboxylic acid end groups. An example ofcapillary in-growth to the domain provided by the first component may befacilitated by the release of angiogenic factors 980. One embodimentincludes microparticles containing angiogenic factors 980 that releaserapidly after introduction to the infarct region. This tends to resultin a rapid angiogenic response.

Biomaterials have been employed to conduct and accelerate otherwisenaturally occurring phenomena, such as tissue regeneration in woundhealing in an otherwise healthy subject; to induce cellular responsesthat might not normally be present, such as healing in a diseasedsubject or the generation of a new vascular bed to receive a subsequentcell transplant; and to block natural phenomena, such as the immunerejection of cell transplants from other species or the transmission ofgrowth factor signals that stimulate scar formation in certainsituations.

Component 2:

A second component 640 of the multi component composition according tothe method may be an acrylate agent that is biocompatible. A secondcomponent serves in one aspect to disperse the first component in orderto form a more uniform scaffold over the entire infarct zone and mayinclude border zone as well. It may be an oligomeric di- (or multi-)functional acrylate agent 930 based on a component that isbiocompatible. An embodiment of the two-component composition mayinclude a second component 930 comprising the following groupdi-acryloyl polyethylene glycol, tetra-acryloyl polyethylene glycol(PEG) or (acrylamidomethyl) cellulose acetate proprionate. In order todissolve the acrylamide functional cellulose component ethanol or abiocompatible is required. The second component 930 disperses themicroparticles. 970/990 acting as a suspending media. It is known thatPEG-coated microparticles 990 are less inflammatory and are seen not toelicit a fibrotic response. Thus, it in one aspect may serve as ananti-opsonization agent. Thus, they serve as a camouflage from theimmune system for introduction of the microparticles to the infarctregion. One embodiment includes the injection of both the growth factorcontaining microparticles and the scaffold-forming matrix (acryloylfunctional macromer) using a dual bore needle. FIG. 9D illustrates thefinal formation of the scaffold gel 915. The introduction of the twosolutions simultaneously creates the near instantaneous (around 10seconds) formation of the gel with a microparticle network imbeddedwithin the scaffolding FIG. 915. As the microparticles 925 decompose,growth factors are released promoting the capillary formation within thematrix. In addition, cells begin to grow in the infarct area 935. Thesecells release proteases that may result in the decomposition of thescaffolding ultimately creating additional area for cellular in-growth.In addition, the cells secrete their own extracellular matrix, thepolymer degrades and the resulting tissue may eventually become acompletely natural environment. The decomposition products may becleared from the area by the renal system since capillary re-growth mayoccur.

Component 3:

Another component of a multi component composition and method isillustrated in 650 and 905. A third component includes one of thefollowing: thiol-containing peptide or a di- or multi-functionalbiocompatible such as dithio-PEG. An example of a thiol-containingpeptide 905 may be polycysteine oligomers. An example of this is aprotected form of a polycysteine oligomer, Poly-S-CBZ-L-cysteine orPoly-S-benzyl-L-cysteine (Sigma Chemical P0263 and P7639 respectively).These agents can be de-protected using standard organic chemistryprotocols (Berger et. al. “Poly-L-cysteine” J. Am. Chem. Soc 78, 4483(1956)). The preparation of these thiol-containing agents is well known(Zervas, L. et. al. “On Cysteine and Cystine Peptides” J. Am. Chem. Soc.85:9 1337-1341, (1963)). Additional agents that may function as thethird component of a multi-component composition may be a naturallyoccurring peptides. In one embodiment, the third component of themulti-component scaffolding may be one of the following consisting ofPoly-S-CBZ-L-cysteine and Poly-S-benzyl-L-cysteine. In anotherembodiment of a multi-component composition, the third component of themulti-component scaffolding may be a naturally occurring peptide. In afurther embodiment of a multi-component composition the third componentof a multi-component scaffolding may be the naturally occurring peptideglycine-cysteine-tyrosine-lysine-asparagine-arginine-asparticacid-cysteine-glycine peptide sequence. The third component preferablycontains at least two thiol groups. FIGS. 9A-9F illustrate theintroduction of the three components to the infarct region to treat anMI. One embodiment may be the introduction of the first component andthe second component 920/930 through a dual bore needle and then theintroduction of a thiol-containing third component 905 through a secondneedle. FIG. 9D illustrates a schematic of the final structure 915 thatsubsequently recruits fibroblast growth 935 and capillary 945 in-growthinto the infarct region. The thiol-containing component 905 may be usedto decrease the rate of decomposition of the scaffold and controlrelease of the fibroblast recruiting components of the microparticles.

Any one or more catheters may be used to deliver the any one or multiplecomponents of the embodiments to the infarct region area. Severalcatheters have been designed in order to precisely deliver agents to adamaged region within the heart for example an infarct region. Severalof these catheters have been described (U.S. Pat. Nos. 6,309,370;6,432,119; 6,485,481). The delivery device may include an apparatus forintracardiac drug administration, including a sensor for positioningwithin the heart, a delivery device to administer the desired agent andamount at the site of the position sensor.

Multi Component System for Infarct Reconstruction and InfarctReoxygenation.

The progression of heart failure after an MI is a result of theremodeling of the heart after infarct. In the remodeling processes theheart becomes thinner and the diameter increases in response to adecrease in heart output, in an effort to maintain a continual cardiacoutput. This process of thinning results in an increase in the radius ofthe heart and the stresses on the heart increase.

It has been shown that perfluorocarbon compounds have a high affinityfor gases, for example carbon dioxide and oxygen. The ability ofperfluorocarbons to transport oxygen is approximately eighteen timesgreater than blood plasma in a comparable volume of each component. Inaddition, it was shown that the half-life for oxygenation/deoxygenationis approximately three and one half times faster for many perfluoratedcompounds as compared to hemoglobin. Thus, perfluoro compounds may beused in tissues to aid in the reoxygenation of an affected region suchas an infarct region. A few examples that demonstrate biocompatibilityin a subject are identified in Table 1.

TABLE 1 Compound Properties Trade O₂ solu- Name or Vapor bility atCommon Chemical Name and Molecular Pressure 37° C. Name Structure Weight(mmHg) (V %) F-44E 1,2-bis(perfluoro- 462 12.6 50 butyl)ethaneF₉C₄—CH═CH—C₄F₉ F-66E or 1-perfluoropropane-2- 664 2.3 41 F-i66Eperfluorohexyl)ethane F₇C₃—CH═CH—C₆F₁₃ FDC Perfluorodecalin 462 12.5 45C₁₀F₁₈

FIG. 7 illustrates the multi-component system in a flowchart. Themyocardial infarction is located 720. Then, the components are deliveredto the region via a minimally invasive procedure by methods previouslydescribed and/or by catheter delivery. It was previously disclosed thatthe addition of a thiol functionality FIG. 6 component 3 in the presenceof an electron deficient double bond, such as an acyloyl functionalityFIG. 6 component 2, can undergo a Michael addition. Under basicconditions the thiol functionality becomes hypemucleophillic and rapidly(<<10 seconds) forms a bond with the acryloyl functionality (see FIG.10). As illustrated in FIG. 6, a gel may be formed to prevent infarctexpansion and/or bulking thus preventing a remodeling of the heart thatmay lead to heart failure. FIG. 7 730 illustrates the first componentthat includes a bioerodible gel and 740 illustrate the gel accompaniedby a perfluorinated compound as the second component to enhanceoxygenation of the tissue. The gel is formed by a three-componentsystem. The first component includes a biocompatible polymer aspreviously described with a multifunctional spacer group 730. The secondcomponent 840 includes a di-functional or multifunctional perfluorinatedmolecule 810. The third component 750 includes a hetero-functionalmolecule with a reactive functionality on one side of the spacer group,and a cell binding peptide sequence, such as the peptide sequencespreviously described, on the terminal end. One example of a peptidesequence includes the RGD sequence. FIG. 8 illustrates in schematic formthe reaction of the thiol component 800 and the acyloyl functional group820 to form one compound 830 of the three-component system of FIG. 7.This three-component system may be introduced to the infarct region bysimilar minimally invasive methods as described for the methods of FIG.6 that may be guided by mapping the heart prior to administration of anagent. Examples of this three-component system are discussed in theexample section.

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 100 μl. In a preferred embodiment, the any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 50 μl. IV, and IC routes may be required which wouldinvolve larger treatment volumes (for example about 2 mls to about 250mls).

FIG. 10 illustrates the ester bond formed between the second component(1000) and the third component (1010) of a multi-component compositionof FIG. 6. This bond (1020) is necessary for delaying the degradation ofthe scaffolding and release of the active agents within themicroparticles. This bond tends to resist degradation for approximately2 months.

Swellable Agent Systems for Reinforcement.

FIGS. 11A-11F illustrates the introduction of a swellable non-biologicmaterial to structurally reinforce and/or bulk the infarct region. FIG.11A illustrates the introduction of microparticles 1130 to an infarctregion 1110. Microparticles 1130 are shown accumulated in a mass at thesite of the left ventricle 1100 within the infarct zone. One method forintroduction of the microparticles 1120 is percutaneously with the useof a catheter 1130. A distal end of the catheter is advanced to theinfarct region 1110 and the microparticles 1130 are released. Themicroparticles become lodged in the infarct tissue 1140. FIG. 11Billustrates microparticles 1130 acquiring the necessary surroundingfluid 1150 to swell 1160/1170. One embodiment includes the use ofmicroparticle beads capable of fluid uptake in the infarct region tostructurally reinforce the region. The particles will range in size fromapproximately 5 to approximately 10 microns. The microparticles will beless than 10 microns so that the completely swollen particle becomeslodged in the site (1180) but is not too large to become an obstructionin the area. In addition, the swollen microparticles provide mechanicalstrength and thickness to the damaged area by replacing the dead anddegraded myocardial cells.

1. Agents.

a. Hydrogels Spheres.

Examples include hydrogel spheres composed of cross-linkedpolyacrylamide or cross-linked PVP. The monomeric form of these productswill contain di-functional monomers such as di-vinyl benzene, ethyleneglycol dimethylacrylate or bis acrylamido acetic acid. These agents forma cross-linked network that is resistant to dissolution in aqueoussystems.

b. Commercial Products.

Several commercial products are available that may be used such asmicroparticles obtained from A.P. Pharma or Biosphere Medical. Thesemicroparticles resist non-specific protein absorption and havebio-stable backbone linkages. These microparticles are not bioerodibleor bioabsorbable. FIG. 11E illustrates the microparticles dispersed inthe infarct region taking up the surrounding fluid and swelling untilthey become lodged in the region (FIG. 11F).

Structural Reinforcement Compositions and Materials.

FIG. 12 illustrates several possible methods to reinforce theventricular wall of the infarct region of an MI subject. Restraining theinfarct zone by suturing an epicardial polymer mesh was previouslydemonstrated (Kelley et al., Circ., 1999; 135-142). Due to the nature ofthis technique suturing the mesh directly into the tissue was necessary.This may cause further damage. This procedure requires invasive surgery.In addition, the polymer mesh does not degrade over time and this mayalso be a problem. By injecting a reinforcing agent directly into theaffected area by minimally invasive procedures, this avoids theintrusive suturing protocol. The solution may be injected in the infarctzone during an open chest procedure. In one embodiment, the introductionof the reinforcing solution comprises the following proceduresconsisting of sub-xiphoid and percutaneously. In another embodiment, themode of introduction of the reinforcing solution by a percutaneousinjection comprises one of the following consisting of anintraventricular catheter, a transvascular needle catheter andretrograde venous perfusion.

1. Single Component Systems.

FIG. 12 1210/1220/1230 illustrate the identification and reinforcementof the MI region prior to intervention by a reinforcing agent. FIG. 121210 describes the use of a single component injected into the infarctregion. This example constitutes a single pseudoplastic or thixotropicmaterial capable of forming a gel-like reinforcement to the infarctregion wall. Several examples of these materials exist. In oneembodiment, the structural reinforcing agent includes one of thefollowing consisting of hyaluronic acid, bovine collagen, high-molecularweight ultra-pure polyacrylamide and polyvinyl pyrrolidone.

In one specific embodiment of the present invention, the singlecomponent for structural reinforcement comprises bovine collagendispersed with PMMA (polymethyl methylacrylate) beads. These beads maybe manufactured under the trade name of ARTECOLL (Rofil MedicalInternational, Breda, The Netherlands). PMMA is one of severalcross-linked or highly insoluble microparticles. PMMA was discovered inthe early 1900's and was used initially in dental prosthesis. Recently,it has been used in bone replacement of the jaw and hip. In addition, ithas been used for artificial eye lenses, pacemakers and dentures.ARTECOLL™ has principally been used in filling folds and wrinkles of theface, augmenting lips, adjusting an irregular nose.

Possibly one of the most important features of the insolublemicroparticles is the surface of the microparticles must be smooth toinduce collagen deposition. A rough surface promotes macrophage activitywhile discouraging collagen deposition. The methods incorporate the useof smooth surface particles. The components may act as a substrate forendogenous collagen deposition. As the reinforcing gel degrades, thehighly stable and smooth microparticles may be exposed to the fibroblastcell population occupying the site. This triggers the production ofcollagen to replace the decomposing gel. Therefore, the infarct zone maybe reinforced by the collagen replacement of the temporary gel. In oneembodiment, the dispersing material includes one of the following groupof microparticle materials consisting of PMMA (polymethylmethylacrylate), P(MMA-co BMA) (polymethyl methylacrylate-co butylmethylacrylate), carbon microparticles (Durasphere), polystyrene,cross-linked acrylic hydrogels and PLGA. In another embodiment, thecross-linked acrylic hydrogel may include the following HEMA(2-hydroxyethyl methacrylate), AA (acrylic acid), AMPS(acrylamido-methyl-propane sulfonate), acrylamide, N,N, di-methylacrylamide, diacetone acrylamide, styrene sulfonate, and di- ortri-functional monomers. The di or tri-functional monomers may be EGDMA(ethylene glycol dimethacrylate) and DVB (di-vinyl benzene). Inaddition, the use of highly crystalline (and hydrolysis resistant) PLGAmicroparticles may outlast the carrier gel and also provide a usefulsubstrate for collagen deposition.

Another single solution introduced to the infarct zone may be hyaluronicacid dissolved in sodium salt in water. This is a manufactured gel soldas a dermal augmentation gel (RESTYLANE™). Hyaluronic acid hydrogel hasalso been used in the past for control of delivery of therapeutic agentsin wound sites (Luo, Y. et al. Cross-linked hyaluronic acid hydrogelfilms: new biomaterials for drug delivery” Journal of Controlled Release(2000) 69:169-184). Other possible single introduced components includebovine collagen (ZYDERIVI™ or ZYPLAST™), another dermal augmentation geldeveloped by Collagen Corp. The high molecular weight, ultrapurepolyacrylamide in water may be FORIVIACRYL™ or BIOFORM™ other dermalaugmentation gels. The bovine collagen may be dispersed by the PMMAproduct ARTECOLL™. ARTECOLL™ is best known for its success as abiocompatible dermal augmentation gel for reconstruction. RESOPLAST™(Rofil Medical International, Breda, The Netherlands) may also be usedas a single component gel.

FIG. 12 1220 illustrates another method to reinforce the infarct zone ofthe ventricle using a single component system. This example utilizes theintroduction of a single component that forms a gel after reacting withan endogenous component. One such component may be tropoelastin(detailed previously). Elastin is the insoluble, elastic protein of hightensile strength found in connective tissue of the large arteries,trachea, bronchi and ligaments. Rarely seen endogenously as tropoelastin(the uncross-linked form), it rapidly cross-links to lysine residues ina process of oxidative deamination by the enzyme lysyl oxidase whenintroduced in vivo. As stated previously, tropoelastin is availablecommercially as a recombinant bacterial product. When heated in watertropoelastin forms a coacervate and this may be injected into theinfarct region where lysyl oxidase induces lysine cross-linking by theoxidative deamination process. In one embodiment, tropoelastin may beintroduced to the infarct region. In another embodiment, tropoelastinmay be introduced to the infarct region after the introduction of thehighly insoluble microparticles described above. Another reactivesingle-component may be cyanoacrylate adhesive. This is a widely usedplastics binding agent. In one embodiment the cyanoacrylate may be octylcyanoacrylate. The octyl cyanoacrylate may be the manufactured productcalled Dermabond™ (Johnson and Johnson). This product was recentlyapproved for use as a tissue adhesive for wound closure. Octylcyanoacrylate may be introduced to the infarct region as a liquid. Onceit contacts the infarct region, it solidifies due to its exposure tomoisture. In another embodiment, the octyl cyanoacrylate may beintroduced to the infarct region after the introduction of the highlyinsoluble, stable microparticles described above.

In another embodiment, a reactive single component includes a componentthat is temperature sensitive. This is illustrated in FIG. 12 1230. Oneexample of this type of component is a component that may be a liquid atroom temperature and once exposed to a temperature approximately equalto body temperature the component gels. A more specific componentincludes introducing block co-polymers of silk protein-like sub unitsand elastin-like sub units. An example of the block co-polymer syntheticprotein may be ProLastin (PPTI, Protein Polymer Technologies). Thesecomponents gel due to non-covalent interactions (hydrogen bonding andcrystallization of silk-like subunits) at elevated temperatures forexample approximately equal to body temperature. With these components,no lysine residues are present, so cross-linking due to endogenous lysyloxidase does not occur. The formation of the gel via a change intemperature may be adjusted using additives. These additives include butare not limited to sodium chloride, Diglyme (Diethylene Glycol DimethylEther; 2-Methoxyethyl Ether; Bis(2-Methoxy Ethyl Ether), and ethanol.

Many thermal reversible materials may be used for reinforcement of themyocardial tissue. Generally, thermal reversible components attemperatures of approximately 37 degrees Celsius and below are liquid orsoft gel. When the temperature shifts to 37 degrees Celcius or above,the thermal reversible components tend to harden. In one embodiment, thetemperature sensitive structurally reinforcing component may be Triblockpoly(lactide-co-glycolide)-polyethylene glycol copolymer. This iscommercially available (REGEL™ Macromed, Utah). In another embodiment,the temperature sensitive structurally reinforcing component may includethe following consisting of poly(N-isopropylacrylamide) and copolymersof polyacrylic acid and poly(N-isopropylacrylamide). Another temperaturesensitive structurally reinforcing component commercially available isPLURONICS™ (aqueous solutions of PEO-PPO-PEO (poly(ethyleneoxide)-poly(propylene oxide)-poly(ethylene oxide) tri-block copolymersBASF, N.J.) (Huang, K. et al. “Synthesis and Characterization ofSelf-Assembling Block copolymers Containing Bioadhesive End Groups”Biomacromolecules 2002, 3, 397-406). Another embodiment includescombining two or more of the single components in order to structurallyreinforce the infarct region. For example, silk-elastin, collagen andLaminin may be used as a one-part system. The silk-elastin would likelyform in situ cross-links due to the silk blocks.

In another embodiment, a reactive single component includes a componentthat is pH sensitive. The component remains in a liquid state if it issufficiently protonated preventing gelation. In another embodiment, thecomponent is initially maintained at a low pH for example pH 3.0 andlater introduced to the treatment area that results in gelation of thecomponent due to the physiological pH of the environment. One example ofthis is discussed in Example 3. Several possible cationic agents may bebut are not limited to one of the following cationic agents that remainprotonated at low pH, poly(allyl amine), DEAE-Dextran, ethoxylatedPoly(ethylenimine), and Poly(lysine). Other examples may one of but arenot limited to the following anionic agents for example, dextransulfate, carboxymethyl dextran, carboxymethylcellulose, polystyrenesulfanate and chrondroitin sulfate.

Additionally, any of these microparticle components may be accompaniedby one or more contrast agent and/or suitable agent(s) for treatment ofthe region. The contrast agent or treatment agent may be conjugated toor dissolved into the structural component prior to introduction to theinfarct area. The agents that may accompany the reinforcing component(s)may include but are not limited to angiogenic agents, ACE inhibitors,angiotensin receptor blockers, SRCA (sercoplasmic reticulum calciumpump) pump increasing agents, phospholamban inhibitors andanti-apoptotic drugs. These agents may be in the form of smallmolecules, peptides, proteins or gene products. The small molecules maybe optionally conjugated to a component of the solution, dispersed insolution, or dissolved in solution to improve the adhesion of thereinforcing components to the tissue. One embodiment is to conjugate apeptide with a conserved region that mediates adhesion processes. Aconserved region of a peptide may be a sequence of amino acids having aspecial function of identification that has been conserved in a proteinfamily over time. Another embodiment includes the use of a specificpeptide conjugate with a conserved RGD(arginine(R)-glycine(G)-asparagine-(D)) motif in the presence of thereinforcing component. In further embodiments, the RGD motif peptide mayinclude the following such as von Willebrand factor, osteopontin,fibronectin, fibrinogen, vitronectin, laminin and collagen. Oneembodiment seeks to minimize thinning during remodeling of the infarctregion. Thus, bulking and reinforcing the infarct region post-MI maypreserve the geometry of the ventricle.

Any one or more catheters may be used to deliver the any one or multiplecomponents of the embodiments to the infarct region area. Severalcatheters have been designed in order to precisely deliver agents to adamaged region within the heart for example an infarct region. Severalof these catheters have been described (U.S. Pat. Nos. 6,309,370;6,432,119; 6,485,481). The delivery device may include an apparatus forintracardiac drug administration, including a sensor for positioningwithin the heart, a delivery device to administer the desired agent andamount at the site of the position sensor.

2. Dual Component Systems.

FIG. 12 1240 illustrates the use of dual component systems for theformation of structurally reinforcing gels for application to theinfarct region. Initially, the infarct region is identified by imagingmethods previously discussed 1300. FIG. 131330/1340/1350/1360/1370/1380/1390 illustrates a flowchart furtherdescribing dual component systems of FIG. 13 1360 to form a structurallyreinforcing gel in the infarct region 1320. In one example 1330, twocomponents are combined at the infarct zone at around physiological pH.Component one is a principally anionic solution and the second componentis principally a cationic solution at approximately physiological pH.When the two components are mixed together at the infarct zone, a gelforms rapidly and irreversibly. In one embodiment, a dual componentsystem may comprise poly(acrylic acid) as a first component andpoly(allyl amine) as a second component as illustrated in FIG. 13 1330.In another embodiment, a dual component system may comprise poly(acrylicacid) as a first component and poly(allyl amine) as a second componentthat may be delivered by a catheter with dual injection lumens. Otherdual component systems to form a structurally reinforcing gel in theinfarct region may include elastin as a first component and lysyloxidase as a second component 1340; sodium alginate as a first componentand an aqueous solution of calcium chloride as a second component 1350,and tropoelastin and collagen as a first component and cross-linkerlysyl dehydrogenase as a second component and laminin 1395 may be addedto this combination later. The composition of each component will dependon the mechanical property of the final cross-linked system. Othersubstances that can replace the lysyl dehydrogenase or complement itscross-linking ability might be used such as glutaraldehyde, and/orphotoactivatable crosslinkers for example blue dye used to cross-link.Additionally, these dual component systems may be combined with otherindividual system utilizing commercial products such as AVITENE™(Microfibrillar Collagen Hemostat), SUGICEL™, (absorbable haemostat,Johnson & Johnson), GELFOAM™, FLOSEAL™ (Baxter, matrix hemostaticsealant with a granular physical structure and thrombin), FOCAL SEAL™(Focal, Inc.) or FIBRIN SEAL™ (FS). FLOSEAL™ is a gel constitutingcollagen derived particles and topical thrombin capable of beinginjected. It has been approved for uses including vascular sealing.Several other possible cationic agents may be but are not limited to oneof the following cationic agents that remain protonated at low pH,poly(allyl amine), DEAE-Dextran, ethoxylated Poly(ethylenimine), andPoly(lysine). Other examples may be one of but are not limited to thefollowing anionic agents for example, dextran sulfate, carboxymethyldextran, carboxymethylcellulose, polystyrene sulfanate and chrondroitinsulfate. In a preferred embodiment, the first material may be DEAEDextran and the second material may be polystyrene sulfanate.

FIG. 13 1370 illustrates the use of another dual component system DOPA(3,4-dihydroxyphenyl-L-alanine), a principle component responsible formussel adhesive proteins, capable of forming a hydrogel in conduciveconditions. Specifically, a component known as star block DOPA-block-PEGundergoes cross-linking in situ forming the hydrogel after an oxidationprocess converts the DOPA to O-quinone. This process forms a stable insitu hydrogel. Other examples are represented as dual components in FIG.13 1370/1380. FIG. 13 1380 includes the use of an acrylate macromersolution and a dithiol solution injected into the infarct region forstructural reinforcement. These components when mixed at the infarctsite undergo a cross-linking reaction leading to the formation of ahydrogel. A specific embodiment may comprise the use of PEG triacrylateas the first component and PEG thiol as the second component introducedto the infarct zone via a dual lumen needle system discussed previously.In FIG. 13 1390, a glue-like component system may be employed. Oneembodiment may include the use of GRF glue that is made up of gelatin,resorcinol and formaldehyde (GRF) as a structurally reinforcing agentintroduced to the infarct zone. To accomplish this, a two-part systemmay be used to induce cross-linking upon admixture of the components atthe infarct zone. In other embodiments, the following structurallyreinforcing components may be added along with GRF comprising the groupconsisting of the cross-linking agents polyglutamic acid, polylysine andWSC (water soluble carbodimides).

FIG. 14 illustrates the introduction and action of a single component ordual components to the infarct region for structural reinforcement. FIG.14 illustrates the identification of the infarct region 1410 of theventricle 1400 by methods previously described and subsequentmulti-injection of the separate components to the site of damage 1420.In a dual component system, the two components 1430/1440 contact eachother at the site and form reinforcing structural scaffold 1430/1440. InFIG. 15B, a single pseudoplastic or thixotropic agent is introduced tothe area in multiple injections 1450 and structurally reinforces thewall 1460. These agents are introduced in final form and require noadditional agents. FIG. 14 illustrates the addition of at least oneagent 1430/1440/1450/1480 by multiple injections each at a differentsite 1405/1415 that requires an endogenous component or a temperaturechange 1460/1490 to convert to a structurally reinforcing form1450/1470/1495. The structurally reinforcing agent(s) is localized tothe infarct region via minimally invasive procedures discussedpreviously.

In addition, biocompatible viscosifiers for example type 1 gels may beadded in combination with any of the single or multiple componentsystems illustrated. For example, hyaluronic acid or PVP may be used toincrease the resistance of the active formula from natural degradationonce introduced to the infarct zone. In one embodiment the viscosity ofthe treatment agent may be about 0-100 centipoise. In other embodiments,the viscosity of the treatment agent may be about 0-50 centipoise. In apreferred embodiment, the viscosity of the treatment agent may be about25-40 centipoise. In a preferred embodiment, the viscosity of thetreatment agent may be about 35 centipoise.

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 100 μl. In a preferred embodiment, the any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 50 μl. IV, and IC routes may be required which wouldinvolve larger treatment volumes (for example about 2 mls to about 250mls).

Biocompatible dyes may be added to any single or combination componentsof any of the described embodiments to trace the components in theinfarct region in any procedure. Other dyes may be added forexperimental purposes to trace the deposition of any agent for examplein a rat heart. Some examples of these dyes include but are not limitedto Sudan Red B, Fat Brown RR, Eosin Y and Toluidine blue.

On the other hand, tissue adhesive components may also be added incombination with any of the single or dual component systems illustratedin FIGS. 12, 13 and 14. For example, Laminin-5, polyacrylic acid,Chitosan and water soluble chitosan may be used to increase the tissueretention of the active formulation. Laminin-5 is a basement membraneextracellular matrix macromolecule that provides an attachment substratefor both adhesion and migration in a wide variety of cell types,including epithelial cells, fibroblasts, neurons and leukocytes.Chitosan is the only natural positive ion polysaccharide obtained fromdeacetylated chitin. It possesses decomposability, good membrane formingstate, biocompatibility, anti-fungal and anti-tumor function. Chitosanhas excellent viscosity, compressibility and fluidity.

Single Components Suspended in a Delivery Medium.

FIG. 15 illustrates flowcharts describing other methods to prevent theremodeling and ultimate thinning of the infarct region. As with severalof the previously discussed methods, these methods provide a bulking orstructurally reinforcing agent to the infarct region. In FIG. 15 1510,an agent comprising microparticles in solution (a dispersion) isintroduced to the infarct region after identification of the infarctregion as described previously. The microparticles may be apredetermined range of about 1 to about 200 microns. In one embodiment,the microparticles may be 20 microns or less. In a preferred embodiment,the microparticles may be 10 microns or less. The microparticle sizedelivered to an infarct region may be determined by the delivery methodused. For example an intraventricular catheter may be used to deliverparticles up to 200 microns that may avoid the risk of an embolism. Onesuspending solution for the microparticles may be water. On the otherhand, the suspending solution may also be a solvent, for exampledimethylsulfoxide (DMSO) or ethanol adjuvants. In one embodiment, asuspending solution along with the microparticles may be introduced toas a dispersion an infarct region and the microparticles remain in theregion as the solution dissipates into the surrounding tissue. Thus, themicroparticles provide a structurally reinforcing bulk to the region.This may result in reduction of stress to the post infarct myocardium.It may also serve as a substrate for additional site for collagendeposition. In one embodiment, the dispersion (detailed above) may beinjected in to the infarct zone during an open chest procedure via aminimally invasive procedure. In another embodiment, the minimallyinvasive procedure includes at least one subxiphoid and percutaneously.In another embodiment, the percutaneous introduction into the infarctzone may include one of intra-ventricular needle, transvascular catheterand retrograde venous perfusion.

FIG. 15 1520 illustrates a flow chart of an additional method similar toFIG. 15 1510 except that the microparticles precipitate out of thesolution (the dispersion). In FIG. 15 1520, an agent includingmicroparticles in solution (a dispersion) is introduced to the infarctregion. The microparticles may be a predetermined size of 0 to 200microns. In a preferred embodiment, the microparticles are 10 microns orless. In one embodiment, the suspending solution along with themicroparticles may be introduced to the infarct region and themicroparticles precipitate out of the dispersion in the region. Thus,the microparticles provide a structurally reinforcing bulk to theregion. This may result in reduction of stress to the post infarctmyocardium. It may also serve as a substrate for additional site forcollagen deposition. In one embodiment, the dispersion (detailed above)may be injected in to the infarct zone during an open chest procedurevia a minimally invasive procedure. In another embodiment, a minimallyinvasive procedure including the following of sub-xiphoid andpercutaneously may be employed. In another embodiment, a percutaneousintroduction into the infarct zone may include one of the ofintra-ventricular needle, transvascular needle catheter and retrogradevenous perfusion.

Several examples of the microparticles of FIGS. 15 1510 and 15 1520 areillustrated in FIG. 16. FIG. 16 1610 illustrates the viscous liquidsucrose acetate isobutyrate (SAIB). SAIB is water insoluble. SAIB may bedissolved in a solvent or a combination of solvents for example,ethanol, dimethylsulfoxide, ethyl lactate, ethyl acetate, benzylalcohol, triacetin, 2-pyrrolidone, N-methylpyrrolidone, propylenecarbonate or glycofurol. These solvents decrease the viscosity of SAIBin order to facilitate the introduction of this agent through a needleor lumen. In one embodiment, SAIB may be introduced accompanied by asolvent to the infarct region and the solvent dissipates at the siteleaving behind the viscous SAIB in the region.

Other biocompatible polymer systems may be introduced to an infarct zone(FIG. 16 1620). Some of these agents are not only biocompatible but alsosubstantially water insoluble similar to SAIB. Solvents or mixtures ofsolvents may be used to dissolve the polymer in order to facilitateintroduction to the infarct zone. In one embodiment, a biocompatiblewater insoluble polymer may include the following consisting ofpolylactides, polyglycolides, polycaprolactones, polyanhydrides,polyalkylene oxates, polyamides, polyurethanes, polyesteramides,polydioxanones, polyhydroxyvalerates, polyacetals, polyketals,polycarbonates, polyorthoesters, polyphosphazenes, polyhydroxybutyrates,polyalkylene succinates, and poly(amino acids). Any one of theseinsoluble polymers may be dissolved in solvents for example Diglyme,dimethyl isosorbide, N-methyl-2-pyrrolidone, 2-pyrrolidone, glycerol,propylene glycol, ethanol, tetraglycol, diethyl succinate, solketal,ethyl acetate, ethyl lactate, ethyl butyrate, dibutyl malonate, tributylcitrate, tri-n-hexyl acetylcitrate, dietyl glutarate, diethyl malonate,triethyl citrate, triacetin, tributyrin, diethyl carbonate, propylenecarbonate acetone, methyl ethyl ketone, dimethyl sulfoxide dimethylsulfone, tetrahydrofuran, capralactum, N,N-diethyl-m-toluamide,1-dodecylazacycloheptan-2-one,1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone and glycerol formalto form an injectable polymer solution. The dispersion may be introducedinto the infarct region of the heart where the solvent may dissipate andthe polymer may precipitate out of the dispersion to structurallyreinforce the infarct regional wall. In one embodiment, the disclosedpolymers may be used in any combination as co-polymers of two or morepolymers introduced to the infarct region.

FIG. 16 1630 illustrates a flowchart describing the use of a vinylpolymer and acrylate biocompatible polymer system. Once injected into aninfarct zone, the vinyl polymer/acrylate agent contacts water and thepolymer precipitates thus reinforcing the surrounding tissue of theinfarct region. In one embodiment, the vinyl polymer/acrylate agentincludes the following such as polyvinyl butyral, PBMA-HEMA, PEMA-HEMA,PMMA-HEMA and other acrylate copolymers that dissolve in ethanol,acetone and I-PA. In another embodiment, the vinyl polymer/acrylateagent introduced to the infarct region may be EVAL™ that has a solidphase or melt phase forming process. EVAL™ Resins have a highcrystalline structure. Thermoforming grades of EVAL™ resins havemonoclinic crystalline structure while most polyolefins have either ahexagonal or orthorhombic type structure. This characteristic providesflexibility within its thermoforming capabilities. In anotherembodiment, the vinyl polymer/acrylate agent introduced to the infarctregion may be BUTVAR™ (polyvinyl butyral). In one embodiment, the agentmay be P(BMA co-MMA) (Aldrich Chem.) in Diglyme. In another embodiment,the agent may be EVAL™, a co-polymer of ethylene and vinyl alcohol (EVALCo. of America, Houston, Tex.) in dimethyl acetamide. In anotherembodiment, the polymer may be PLGA (poly(lactide co-glycolide)(Birmingham Polymers, Birmingham, Ala.) in Diglyme.

Other components may act as a substrate for endogenous collagendeposition and protect the precipitated or remaining microparticlesdescribed in FIG. 16 from erosion. As the reinforcing gel degrades, thehighly stable and smooth microparticles may be exposed to the fibroblastcell population occupying the site. This triggers the production ofcollagen to replace the decomposing gel. Therefore, the infarct zone maybe reinforced by the collagen replacement of the temporary gel. Thedispersed material includes the following group of microparticlematerials consisting of PMMA, P(MMA-co BMA), carbon microparticles(Durasphere), poly styrene, cross-linked acrylic hydrogels and PLGA. Inanother embodiment, the cross-linked acrylic hydrogel may include thefollowing for example HEMA, AA, AMPS, acrylamide, N,N, di-methylacrylamide, diacetone acrylamide, styrene sulfonate, and di or trifunctional monomers. The di or tri-functional monomers may be EGDMA andDVB. Another example of durable microparticles includes pyrolyticcarbon-coated microparticles. One example of pyrolytic carbon-coatedmicroparticles was originally produced for urinary incontinence (CarbonMedical Technologies) and trisacryl gelatin microparticles for use asembolization particles (Biosphere). In addition, the use of highlycrystalline (and hydrolysis resistant) PLGA microparticles may outlastthe carrier gel and also provide a useful substrate for collagendeposition.

One or more contrast agents 1540 and/or suitable treatment agent(s) 1550may accompany the previously detailed components as a treatment of theinfarct region. The contrast agent or treatment agent may be conjugatedto or dissolved into the structural component prior to introduction tothe infarct area. The contrast agents may be used for detection in X-rayor MR analysis. The agents that may accompany the reinforcingcomponent(s) may include but are not limited to angiogenic agents, ACEinhibitors, angiotensin receptor blockers, SRCA pump (sarcoplasmicreticulum calcium pump) increasing agents, phospholamban inhibitors andanti-apoptotic drugs. These agents may be in the form of smallmolecules, peptides, proteins or gene products. The small molecules maybe optionally conjugated to a component of the solution, dispersed insolution, or dissolved in solution to improve the adhesion of thereinforcing components to the tissue. One embodiment is to conjugate apeptide with a conserved region that mediates adhesion processes.Another embodiment includes the use of a specific peptide conjugate witha RGD (arginine-glycine-asparagine) motif in the presence of thereinforcing component. In further embodiments, the RGD motif peptide mayinclude von Willebrand factor, osteopontin, fibronectin, fibrinogen,vitronectin, laminin and collagen.

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 100 μl. In a preferred embodiment, the any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 50 μl.

Collagen Cross-Linking Agents for Structural Reinforcement

FIG. 17 illustrates a flowchart describing a method to structurallyreinforce the infarct region of the ventricle 1710. As previouslymentioned, thinning is a key factor in the cascade of events followingremodeling of the infarct region. One factor contributing to thethinning is collagen degradation by MMPs (matrix metalloproteins) andcollagen helix slippage due to hemodynamic stress. The collagen slippagegenerates infarct scar expansion that leads to additional remodeling andremote zone hypertrophy. Previous inventions to prevent collagenslippage include a suturing procedure (Kelley et al., Circ., 1999;99:135-142). This involves directly suturing an epicardial polymer meshto the region. According to one embodiment, agents will be introduced tothe region by a minimally invasive procedure to prevent collagenslippage. An agent or dispersion will be introduced in one embodiment bymultiple injections to the infarct zone then the agent will react withthe collagen scar directly to cross-link it. This results in preventionof slippage and strength to the regional wall. In one embodiment, theagent (detailed above) may be injected in to the infarct zone during anopen chest procedure via a minimally invasive procedure. In anotherembodiment, the minimally invasive procedure may include sub-xiphoid andpercutaneously. In another embodiment, the percutaneous introductioninto the infarct zone may comprise one of intra-ventricular needle,transvascular needle catheter and retrograde venous perfusion.

A contrast agent or treatment agent may be conjugated to or dissolvedinto the structural component prior to introduction to the infarct area.

Several possible cross-linking agents are illustrated in FIG. 18 toillustrate the possible agents of 1720 to prevent collagen slippage1730. The agent injected into the infarct region may be polyfunctional(either hetero or homopolymer). Another important feature of thecross-linking agent is the ability of the agent to cross-link to theside groups of the amino acids of the collagen (type I and III). In oneembodiment, the agent is soluble in a biocompatible water misciblesolvent that is capable of being drawn out of the dispersion by aqueousfluid present in the myocardium. T his enables the cross-linking agentthe ability to precipitate out into the infarct region minimizingmigration of the cross-linking agent out of the area. In anotherembodiment, the biocompatible solvent used in the presence of thecross-linking agent may be the following Diglyme and dimethylisosorbide. Collagen is made up of a large number of lysine andhydroxyproline residues that carry reactive side groups of primaryamines and hydroxyl groups respectively. In the following examples, thecross-linking agents react with at least one of these side groups. FIG.18 1810 illustrates a flowchart describing a method using polyepoxyfunctional resins for cross-linking the collagen. In one embodiment apolyepoxyl functional resin may be introduced to the infarct region. Inanother embodiment, the polyepoxy functional resin may comprise thefollowing consisting of Bisphenol A epoxies (Shell 828), Epoxy-Novolakresins (Ciba 1138 and 1139, Dow 431), homopolymers of glycidylmethacrylate (GMA) or copolymers of GMA with other acrylates. In anotherembodiment, the polyepoxy functional resins may include amultifunctional epoxide. In another embodiment, the polyepoxy functionalresins may include an acrylate. The later resins, multifunctionalepoxides and acrylate, are based on a cubic silicone with eight epoxideor acrylate functionalities (Silsesquixanes). In another embodiment, thepolyepoxy functional resins may include a tetra-functional epoxidesilicone. In another embodiment, the polyepoxy functional resins mayinclude di-functional epoxide silicone.

FIG. 18 1820 illustrates a flowchart describing the use ofpolyisocyanates as the cross-lining agent. In one embodiment, thecross-linking agent used to link the collagen may comprise apolyisocyanate. In another, the polyisocyanate may include the followingthe biuret of hexamethylene di-isocyanate and isocyanurate ofhexamethylene di-isocyanate. Both of these products are manufacturedcommercially under the name DESMODUR N 100 and DESMODUR 3300respectively (commercially available from Bayer). FIG. 18 1830illustrates a flowchart describing the use of aromatic halogenatedcompounds as a possible collagen cross-linking agent. In one embodiment,the agent used to cross-link the collagen to prevent slippage andstructurally reinforce the infarct region may include a halogenatedcompound. In another embodiment, the halogen compound used to cross-linkthe collagen may include 1,5 difluoro 2,4 dinitrobenzene (DFNB).

Polyhydroxyl aromatics (resorcinol groups) such as vegetable tanninshave been used to cross-link collagen for processing animal hides intoleather. FIG. 18 illustrates a flowchart describing the use of theseresorcinol groups for collagen cross-linking Solvent solubleresorcinol-formaldehyde resins contain numerous resorcinol groups. Amethylene bridge and/or an ether bridge connect the resorcinol groups.RESORCINOL™ is capable of cross-linking collagen but one problem is thatit is corrosive and water miscible in its monomeric form. In oneembodiment, the cross-linking agent to secure the collagen andstructurally reinforce the infarct region may be aresorcinol-formaldehyde resin.

FIG. 18 1850 illustrates a flowchart describing the use of agents thatterminate in an acrylate group as a potential cross-linking agent toprevent collagen slippage in the infarct region and structurallyreinforce the ventricular wall. These acrylate-terminating agents reactwith the primary amine groups of the collagen and form a stabilizingcross-link. In one embodiment, the cross-linking agent may be anacrylate-terminating agent. In another embodiment, theacrylate-terminating agent used to cross-link the collagen may includeone of the following water-insoluble agents urethane-acrylates andepoxy-acrylates. These compounds are commercially available (CognisCorp, Ohio). Another example of a cross-linking agent is illustrated inthe flowchart of FIG. 18 1860. Lysyl oxidase discussed earlier may beuse alone or in combination with other agents to cross-link the collagenfor prevention of slippage and as a structurally reinforcing agent inthe infarct region. Lysyl oxidase is an enzyme that oxidativelydeaminates lysine side groups and forms reactive aldehyde groups capableof forming strong cross-linking bonds with the collagen. In oneembodiment, lysyl oxidase may be introduced to the infarct region tocross-link the existing collagen for prevention of slippage.

In the final flowchart example of FIG. 18 1870 illustrates a flowchartdescribing the use of microparticles to cross-link and stabilize thecollagen in the infarct region. One example includes the use ofsurfactant free styrene latex particles in narrow size distributionsthat also contain the following functional surface groups comprisingchloromethyl, epoxy and aldehyde. The aldehyde surface groups may betightly packed therefore borohydride reduction would not be necessaryfor a stable linkage. Chloromethyl groups react with primary andsecondary amines thus forming a stable cross-link. Other possiblefunctional reacting groups may include succinimidyl ester, benzotriazolecarbonate and p-nitrophenyl carbonate. Other possible functional groupsmay be used. In one embodiment, the size limitation of themicroparticles may include submicron to single digit micron size. Thissize range prevents the microparticles that may backwash out of the sitefrom causing an embolic hazard. In other embodiments, the cross-linkingagent may be a functionalized surfactant free styrene latexmicroparticle. Several examples exist of these styrene microparticles.Examples of commercially available functional stryrene microparticlesare manufactured by Interfacial Dynamics Corporation and Magsphere.

Additionally, any one of these agents illustrated in FIGS. 17 and 18 maybe accompanied by one or more contrast agent 1740 and/or suitableagent(s) 1750 for treatment of the region. The contrast agent ortreatment agent may be conjugated to or dissolved into the structuralcomponent prior to introduction to the infarct area. The agents that mayaccompany the reinforcing component(s) may include but are not limitedto angiogenic agents, ACE inhibitors, angiotensin receptor blockers,SRCA pump increasing agents, phospholamban inhibitors and anti-apoptoticdrugs. These agents may be in the form of small molecules, peptides,proteins or gene products. The small molecules may be optionallyconjugated to a component of the solution, dispersed in solution, ordissolved in solution to improve the adhesion of the reinforcingcomponents to the tissue. One embodiment is to conjugate a peptide witha conserved region that mediates adhesion processes. Another embodimentincludes the use of a specific peptide conjugate with a RGD(arginine-glycine-asparagine) motif in the presence of the reinforcingcomponent. In further embodiments, the RGD motif peptide comprises thefollowing consisting of von Willebrand factor, osteopontin, fibronectin,fibrinogen, vitronectin, laminin and collagen.

Prevention of Myocardial Edema and “Cementing” of the Infarct Region.

FIG. 19 illustrates flowcharts describing the introduction of clottingfactors immediately after an MI 1900. One of the initial responses ofthe process post-MI is myocardial edema. The edema is composed ofextravasated blood evident within a few hours after infarction. This isfollowed by its dissolution within the next few hours. The process thatoccurs immediately post-MI is that the infarct regional wall thickensand then it thins. The present invention illustrated in FIG. 19introduces one or more clotting factors to the region thereby“cementing” the now clotted blood to reinforce the wall and thicken thewall 1910. FIG. 19 1920/1930 illustrates one method to clot the bloodusing a dual solution technique. In one embodiment, the first solutionincludes calcium chloride and thrombin 1920 and the second solution 1930includes fibrinogen and transexamic acid. Transexamic acid is ananti-fibrinolytic agent. The introduction of these two solutions to theinfarct region sequentially result in localized clotting of the bloodthat forms a structurally reinforcing mass 1940 within the regionpreventing thinning of the infarct site. In another embodiment,intravenous pressure perfusion may be used to deliver the clot inducingsolutions to the infarct zone. This prevents the possibility of the clotreleasing into the arterial circulation. FIG. 19 1950 illustrates aflowchart describing the use of shear-activated platelet fraction toinduce localized clotting. This platelet fraction may be isolated fromthe MI subject's own blood or another source. FIG. 19 1960 illustrates aflowchart of other initiators of the clotting cascade. These factorsencompass factors that are termed intrinsic and extrinsic factors.Intrinsic factors initiate clotting in the absence of injury. Extrinsicfactors initiate clotting that is caused by injury. In one embodiment,the clotting factor used to cease myocardial edema and reinforce theventricular wall at the infarct zone may comprise the followingconsisting of von Willebrand Factor (vWF), High Molecular WeightKininogen (HMWK), Fibrinogen, Prothrombin, and Tissue Factors III-X. Inanother embodiment of the present invention, any combination of theclotting factors mentioned previously may be used that may provideincreased tensile strength the infarct regional wall.

Matrix Metalloproteinase Inhibitors Use in the Infarct Region

After an MI injury occurs macrophages tend to infiltrate the infarctregion. The macrophages release matrix metalloproteinases (MMPs). Asmembers of a zinc-containing endoproteinase family, the MMPs havestructural similarities but each enzyme has a different substratespecificity, produced by different cells and have differentinducibilities. These enzymes cause destruction in the infarct zone. Oneimportant structural component destroyed by MMPs is the extracellularmatrix (ECM). The ECM is a complex structural entity surrounding andsupporting cells that are found within mammalian tissues. The ECM isoften referred to as the connective tissue. The ECM is composed of 3major classes of biomolecules; structural proteins: for example collagenand elastin, specialized proteins for example fibrillin, fibronectin,and laminin, and proteoglycans: these are composed of a protein core towhich is attached long chains of repeating disaccharide units termed ofglycosaminoglycans (GAGs) forming extremely complex high molecularweight components of the ECM. Collagen is the principal component of theECM and MMP induce ECM degradation and affect collagen depositionInhibitors of MMP(s) exist 1970 and some of these inhibitors are tissuespecific. It was previously demonstrated that acute pharmacologicalinhibition of MMPs or in some cases a deficiency in MMP-9 that the leftventricle dilatation is attenuated in the infarct heart of a mouse(Creemers, E. et. al. “Matrix Metalloproteinase Inhibition AfterMyocardial Infarction” A New Approach to Prevent Heart Failure? CircRes. Vol 89 No. 5, 2315-2326, 1994). The inhibitors of MMPs are referredto as tissue inhibitors of metalloproteinases (TIMPs). Synthetic formsof MMPIs also exist for example BB-94, AG3340, Ro32-355b and GM 6001. Itwas previously shown that MMPIs reduce the remodeling in the leftventricle by reducing wall thinning. These experiments were performed onrabbits. In addition, this study also demonstrated that MMPI increasesrather than decreases neovascularization in the subendocardium (Lindseyet. al. “Selective matrix metalloproteinase inhibitors reduce leftventricle remodeling but does not inhibit angiogenesis after myocardialinfarction,” Circulation 2002 Feb. 12; 105 (6):753-8). In the oneembodiment MMPIs may be introduced to the infarct region to delay theremodeling process by reducing the migration of fibroblasts anddeposition of collagen and prevent ECM degradation, reduce leukocyteinflux and also reduce wall stress. In one embodiment, the MMPIs mayinclude the following TIMPs including but not limited to TIMP-1, TIMP-2,TIMP-3 and TIMP-4 introduced to the infarct region in combination withintroducing any of the described structurally reinforcing agents to theinfarct region. In another embodiment, naturally occurring inhibitors ofMMPs may be increased by exogenous administration of recombinant TIMPs.In another embodiment, the MMPI comprises a synthetically derived MMPIintroduced to the infarct region in combination with introducing any ofthe described structurally reinforcing agents to the infarct region. Theintroduction of MMPIs to the infarct zone may be accomplished by severaldifferent methods. It is critical that the introduction of these MMPIagents be accomplished by a minimally invasive technique. In oneembodiment, MMPI agents will be introduced to the region by a minimallyinvasive procedure to prevent ECM degradation. An agent or dispersionwill be introduced in one embodiment by multiple injections to theinfarct region. This results in prevention of ECM degradation andincreased strength to the regional wall. In one embodiment, the MMPIagent may be injected in to the infarct zone during an open chestprocedure via a minimally invasive procedure. In another, the minimallyinvasive procedure may include one of sub-xiphoid and percutaneously. Inanother embodiment, the percutaneous introduction into the infarct zonemay include one of intra-ventricular needle, transvascular needlecatheter and retrograde venous perfusion. In addition, the MMPI agentsmay be introduced via suspension or sustained release formula forexample introduced in microparticles detailed in the three-componentsystem of FIG. 6. In one embodiment, the introduction of MMPIs mayfollow any of the cross-linking events that prevent collagen slippage.In another embodiment, the cross-linking agent may be cleared from thetargeted infarct area prior to introducing the MMPI(s).

After an MI, the myocardium may be significantly affected resulting in apercentage of the tissue being akinetic or dyskinetic. This often occurswhen the MI is caused by an occluded left anterior descending artery.Moderate infarct where 20 to 40 percent of the tissue is affecteddecreased cardiac output occurs resulting in the activation of theneurohormonal system (via a RAAS (renin-angiotensin-aldosterone)system). Thus, the neurohormonal activation causes an increase in bloodpressure resulting in further stress to the myocardium. The inducednecrosis results in an inflammatory response that clears the site of thenecrotic tissue and ultimately leads to thinning of the myocardium. Thecycle continues with an increase in stress on the myocardium and mayresult ultimately in heart failure.

Structural Reinforcement of the Infarct Zone by Inducible Gel Systems.

FIG. 20 illustrates a flowchart describing the introduction ofphoto-polymerizable hydrogels to the infarct region for structuralreinforcement of the infarct zone (2000). Hydrogels have been usedbefore in tissue engineering applications. These gels are biocompatibleand do not cause thrombosis or tissue damage. These hydrogels may bephoto-polymerized in vivo and in vitro in the presence of ultraviolet(UV) or visible light depending on the photo initiation system.Photo-polymerizing materials may be spatially and temporally controlledby the polymerization rate. These hydrogels have very fast curing rates.A monomer or macromer form of the hydrogel may be introduced to theinfarct zone for augmentation with a photo initiator. Examples of thesehydrogel materials include PEG acrylate derivatives, PEG methacrylatederivatives or modified polysaccharides.

Visible light 2030/2160 maybe used to initiate interfacialphotopolymerization of a polyoxyethylene glycol(PEG)-co-poly(alpha-hydroxy acid) copolymer 2100 based on PEG 8000macromonomer in the presence of an initiator for example Quanticare QTX.Initiator2-hydroxy-3-[3,4,dimethyl-9-oxo-9H-thioxanthen-2-yloxy]N,N,N-trimethyl-1-propaniumchloride photo-initiator may be obtained as Quantacure QTX. This is aspecific water-soluble photo-initiator that absorbs ultraviolet and/orvisible radiation and forms an excited state that may subsequently reactwith electron-donating sites and may produce free radicals. Thistechnology has been used to demonstrate adherence to porcine aortictissue, resulting in a hydrogel barrier that conformed to the region ofintroduction. The resulting matrix was optimized in vitro and resultedin the formation of a 5-100 microns thick barrier (Lyman, M D et. al.“Characterization of the formation of interfacially photopolymerizedthin hydrogels in contact with arterial tissue Biomaterials” 1996February; 17 (3):359-64). Scaffolding 2040/2130 may be directed to onlythe desired area of the ventricle using minimally invasive proceduresdiscussed previously. The structural reinforcement could remain in placeuntil it is cleared or degraded 2050/2170.

One embodiment includes introduction to the infarct zone of benzoinderivatives, hydroxalkylphenones, benziketals and acetophenonederivatives or similar compounds. These photo-initiators form radicalsupon exposure to UV light by either photocleavage or by hydrogenabstraction to initiate the reaction see FIGS. 21A-21E. The source ofthe UV or visible light may be supplied by means of a catheter 2160 forexample a fiber optic tip catheter or lead on a catheter illustrated inFIG. 21C or transdermally. FIGS. 22A-22B illustrate a catheter assemblythat may be used to deliver a light sensitive material. The catheter2210 is designed to provide a delivery device with at least one lumenfor one or more agent(s) 2230 and a light source 2220 for modificationof the delivered agent. The catheter controller 2240 may house a switch2250 for the light source 2220 and a controller for agent delivery 2260.In another embodiment, the photo-initiator Camphorquinone may be used.Camphorquinone has been used extensively in dental applications and hasa lambda max of 467 nanometers. For example, this agent can be activatedby a GaN blue LED on the tip of a catheter. One embodiment includes theuse of visible light at the end of the delivery catheter to induce thepolymerization event in the presence of a light sensitive initiator.Another embodiment includes the use of the photoinitiator,Camphorquinone that may facilitate the cross-linking of the hydrogel bya light on the tip of a catheter within the infarct region. Anotherembodiment includes the use of the photoinitiator, Quanticare QTX thatmay facilitate the cross-linking of the hydrogel by a light on the tipof a catheter within the infarct region. Another embodiment includes theuse of a catheter with a UVA light source to induce the polymerizationevent in the presence of a light sensitive initiator. Other initiatorsof polymerization in the visible group include water soluble freeradical initiator 2-hydroxy-3-[3,4,dimethyl-9-oxo-9H-thioxanthen-2-yloxy]N,N,N-trimethyl-1-propaniumchloride. This cascade of events provides the necessary environment forinitiation of polymerization of suitable vinyl monomers or pre-polymersin aqueous form within the infarct region (Kinart et. al.Electrochemical studies of2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)N,N,N-trimethyl-1-propaniumchloride” J. Electroanal. Chem 294 (1990) 293-297).

One possible method of introducing a photo-polymerizable agent to theinfarct region is illustrated in FIGS. 21A-21E. In one embodiment thephoto-polymerizable material is introduced to the infarct regions duringan open chest procedure or via a minimally invasive procedure 2130. Inanother embodiment, the minimally invasive procedure includes thefollowing sub-xiphoid and percutaneously. In another embodiment, thepercutaneous introduction into the infarct zone may comprise one of thefollowing consisting of intra-ventricular needle, transvascular needlecatheter and retrograde venous perfusion. A single bore needle catheter2120 may be used to introduce the photo-polymerizable material into theinfarct zone 2140. Once the agent is introduced to the region, severalheartbeats clear the excess agent into the ventricle 2150 and thisexcess agent is cleared from the cardiac region. Once the excessmaterial is cleared, the light source 2160 may be introduced to inducepolymerization 2170. Thus, the structural reinforcement is confined tothe local area of damage where tissue augmentation is required. Asillustrated in FIG. 20, the scaffolding may be made up of a resistantmaterial or a biodegradable material 2050. Some examples ofbiodegradable materials include PEG-co-poly(α-hydroxy acid) diacrylatemacromers, derivatives of this material that vary the length andcomposition of the α-hydroxy acid segment in the co-polymer,polypropylene fumarate-co-ethylene glycol and hyaluronic acidderivatives. The degradation rates of the polymers may be variedaccording to the optimum length of time the material is required toremain in the infarct region. It has been shown that the degradationrates of theses gels can be modified by the appropriate choice of theoligo(α-hydroxy acid) from as little as less than one day to as long as4 months (Sawhney, A. S. et. al., Bioerodible Hydrogels Based onPhotopolymerized Poly(ethylene glycol)-co-poly(α-hydroxy acid)Diacrylare Macromers. Macromolecules (1993) 26, 581-587). Any of thesepolymer chains may be formed in the presence of a photoinitiator such asQuanticare QTX and a light source.

FIGS. 21A-21E illustrate the process of introduction of a potentialphoto-polymerizable material to the infarct zone. FIG. 21A and FIG. 21Billustrate the introduction of the material to the site 2100 and 2110.FIG. 21C illustrates the clearing of the excess material into theventricle 2150. Then, in FIG. 21C the light source may be introduced viaa catheter to polymerize the material 2160. The material remains in thesite 2170 as structural reinforcement until at which time it degrades ornot depending on the material used.

In one embodiment, any of the described agents may be introduced in oneor more doses in a volume of about 1 μl to 1 ml. In another embodiment,any of the described agents may be introduced in one or more doses in avolume of about 1 μl to 300 μl. In another embodiment, any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 100 μl. In a preferred embodiment, the any of thedescribed agents may be introduced in one or more doses in a volume ofabout 1 μl to 50 μl.

FIG. 24A and FIG. 24B illustrate a catheter assembly that may be used todeliver a dual component composition. In FIG. 24A, component 1 2410 andcomponent 2 2420 are housed 2430 in separate lumen of a delivery device.Delivery of the components is controlled by a handle 2470 at the base ofthe device. The handle 2470 is rotated to allow one needle to extend andthen the other. Only one needle is engaged at a time. A cross-sectionalview illustrated in FIG. 24B illustrates the first needle port 2450 andthe second needle port 2460 and the central tendon 2480 that controlsthe needle extension. At the distal end 2490 of the device, FIG. 24C,the handle is turned and the needle extends while retracting the otherneedle. In one embodiment, this catheter device may be used to delivercomponents to the infarct region of a left ventricle intramyocardium. Inanother embodiment, this catheter device may be used to deliver a firstcomponent to the area and a second component after the excess firstcomponent is allowed some time to wash away.

FIGS. 25A-25D illustrates the introduction of dual components using thecatheter device of FIG. 24 to an infarct region while avoiding thepossibility of injecting the agents into the exact same site. Thedelivery device of FIG. 24 is used to deliver the components to theinfarct region. The infarction is illustrated as a region between theendocardium and the epicardium. The device 2540 is advanced to this siteand the first component is delivered by extending needle 1 2550 and thecomponent 2560 is dispersed in the infarct area. Then this needle 2550is retracted while the second needle 2570 is extended. The secondcomponent 2580 is dispersed. The delivery of the two components to thearea is capable of forming a gel 2590.

FIG. 26 illustrates the delivery of the catheter device illustrated inFIGS. 24 and 25. Both of the components are delivered through a lumen ofa catheter (for example a balloon catheter) 2630/2640 at the same time.For example, the first component 2650 may be delivered through a venousroute 2610 and the second component 2660 may be delivered through anarterial route 2620. This procedure ensures the appropriate pressurebalance to contain the components in the microcirculation. This avoidsleakage to either the venous or arterial side. The driving pressure forthe venous side is greater than 100 mm Hg (delta P) 2670 is calculatedto ensure the confinement of the component in capillary level) and thearterial side does not require an external pressure gradient. Thearterial side may be accomplished by infusion. In one embodiment, thecatheter may be used to deliver the first component through the venoustree followed by the second component through the arterial tree. Thisdevice may be used to deliver any of the component combination methodsdescribed in the embodiments detailed previously.

Ventricular Plugs

Another method for reinforcing the damaged wall of a ventricle mayinclude introduction of a solid material to the damaged area. The solidmaterial may be used to fill or bulk the region by introducing plugs ofthe solid material to the site and may increase the compliance of theventricle. These materials may be made of organic or silicon-basedpolymers, biodegradable polymers, non-biodegradable polymers, engineeredbiomaterials and/or metals. In one embodiment the plug may have barbs orpointed ends in order to lodge the material into the area and ensure itremains there. In other embodiments, the sealant or plug may add bulk tothe thinning wall of an infarct post myocardial infarction. This mayresult in an increase in the modulus of elasticity of the damaged area.In other embodiments, the sealant or plug may invoke an inflammatoryresponse to the infarct region. The inflammatory response will result inthe increase in angiogenic response capable of causing recruitment andactivation of fibroblasts that deposit additional collagen to bulk thethinning infarct region and increase the modulus of elasticity of thisregion. Still, other embodiments include the addition of a plug to thedamaged region of a ventricle that may add strength to the wall and alsocause an inflammatory response to the region.

In one embodiment, the plug supplied to the damaged region of theventricle may include biocompatible organic components. In otherembodiments, the plug supplied to the damaged region of the ventriclemay include a biocompatible silicone-based polymer. In otherembodiments, the plug supplied to the damaged region of the ventriclemay include biocompatible biodegradable polymers for example PLGA,Poly(hydroxyvalerate) and poly ortho esters etc. In other embodiments,the plug supplied to the damaged region of the ventricle may includebiocompatible non-biodegradable material for example polypropylene andPMMA. In still further embodiments, the plug supplied to the damagedregion of the ventricle may include biocompatible metal compounds forexample 316L, Co—Cr alloy, Tantalum and titanium etc. Another advantageto using a plug directly implanted in the region of interest may be toadd additional surface components to the plug such as side groups. Theseside groups may contain reactive side groups that react with exogenouslysupplied or endogenous collagen, for example, type I and type IIIcollagen. Since collagen contains a significant number of lysine andhydroxyproline residues, these residues harbor primary amine andhydroxyl groups capable of reacting with other moieties. In oneembodiment, the plug supplied to the damaged region of the ventricle mayinclude surface aldehyde groups capable of reacting with the primaryamines of lysine in collagen.

The size and the shape of the plugs may vary depending on the situation.For example, polymeric plugs mentioned previously may be machined,injection molded, extruded or solution cast. In one embodiment, theshape of the plug may be elongated and thin in order to facilitatedelivery by a catheter device. These plugs may also possess a barb orside protrusion to prevent the plug from slipping out of the site onceit is introduced to the damaged region of the ventricle. In otherembodiments, the plug may be created in the shape similar to a screw ora helix. In one embodiment, the plug may be a polymeric material. Inother embodiments, the plug may be a polymeric material with SS anchorsfor example, a plug with a stainless steel band with anchors forembedding the plug into the site of interest. The size of the plug mayalso vary. In one embodiment, the radial diameter of the plug may befrom about 0.1 mm to about 5 mm. In other embodiments, the radialdiameter of the plug may be about 0.2 mm to about 3 mm. In otherembodiments, the length of the plug may be from about 1 to about 20 mm.In other embodiments, the length of the plug may be about 2 mm to about12 mm. In addition to the size and shape of the plug, the number ofplugs supplied to a region in the ventricle may also vary depending onthe extent of damage and the condition of the subject. In oneembodiment, the number of plugs supplied to the region may about 1 toabout 200. In other embodiments, the number of plugs supplied to theregion may be about 5 to about 50. In still further embodiments, thenumber of plugs supplied to the region may be about 2 to about 20.

In a preferred embodiment, the plug may be a processed biocompatiblebiomaterial. This biomaterial may be advantageous for recruiting cellsto the damaged region for additional strength to the site. One exampleof a biomaterial includes porcine derived Small Intestine Submucosa,termed SIS. This engineered biomaterial may be supplied from DePuy Incand the Cook Group. It is available in sterile sheets. SIS includes thecomplete small intestinal submucosa, including de-cellularizedextracellular matrix (ECM) in a native configuration. It also includesimportant endogenous growth factors adhered to the matrix. SIS haspreviously been shown to recruit pluripotent bone marrow derived stemcells that adhere to the SIS and induce healing. SIS has previously beenused to repair rotator cuff injuries, diabetic foot ulcers and hipjoints. SIS has been shown to re-absorb after a period of approximately3 to 4 months. After re-absorption, the healed live tissue has replacedthe matrix. In one embodiment, small disks of SIS may be supplied to aregion in the ventricle for example an infarct region. The SIS disks mayprovide similar recruitment of cells into the damaged myocardium. Thesecells may then transform into viable muscle tissue and may formcontractile myocytes.

There are several methods that may be used to introduce any of the plugsdescribed. An optimum approach for introduction of the plugs may includebut is not limited to introduction to the infarct region and/or theborder zone of an infarct region during an open-heart procedure; orthrough a minimally invasive procedure for example sub-xiphoid orpercutaneously for example with an intra-ventricular catheter ortransvascular catheter (venous or arterial). One embodiment forintroducing the plugs to the infarct region may include directlyintroducing the plugs to the site during an open-heart surgicalprocedure.

One or more contrast agents and/or suitable treatment agent(s) mayaccompany the previously detailed components. The contrast agent ortreatment agent may be dispersed into, conjugated to, or dissolved intothe plug component prior to introduction to the infarct area. Thecontrast agents may be used for detection in X-ray or MR analysis. Theagents that may accompany the reinforcing component(s) may include butare not limited to angiogenic agents, ACE inhibitors, angiotensinreceptor blockers, SRCA pump (sarcoplasmic reticulum calcium pump)increasing agents, phospholamban inhibitors and anti-apoptotic drugs.These agents may be in the form of small molecules, peptides, proteinsor gene products. The agents may be optionally conjugated to a componentof the resin mix that makes the plug, dispersed in the plug solutionprior to forming the plug, or dissolved in the plug solution prior toforming the plug, or packed into machined pockets or reservoirs in theplug to elicit a biological effect (e.g. improve implant adhesion,recruit cells, promote healing). One embodiment is to conjugate apeptide with a conserved region that mediates adhesion processes.Another embodiment includes the use of a specific peptide conjugate witha RGD (arginine-glycine-asparagine) motif or the peptide receptor toRGD, such as DDM (aspartate-aspartate-methionine) in the presence of thereinforcing component. In further embodiments, the RGD motif peptide mayinclude von Willebrand factor, osteopontin, fibronectin, fibrinogen,vitronectin, laminin and collagen.

In the foregoing specification, the embodiments have been described withreference to specific exemplary embodiments. It will, however, beevident that various modifications and changes may be made withoutdeparting from the broader spirit and scope of the invention as detailedin the appended claims. The specification and drawings are, accordingly,to be regarded in an illustrative rather than a restrictive sense.

EXAMPLES Example 1

Example 1 illustrates one possible three-component system described inFIG. 7 to treat a myocardial infarction. A cross-linking functionalitycan be synthesized starting from a fluorinated molecule with an ethylenefunctionality as in FIG. 22. Bromine 2310 is added to a fluoronatedmolecule 2300. Reduced thiols rapidly replace the bromine groups forminga di-functional thiol component 2320. The di-functional thiol 2330 canthen react with a tetra-acryloyl(polyethylene glycol) 2340 and adifunctional polyethylene glycol with both the thiol functionality andthe RGD 2380 peptide sequence. The tetra-acryloyl(polyethylene glycol)can be obtained from Shearwater Polymers as a specialty polymer (productnumber 0J0000D04; M_(r)=2,000 with each arm having a molecular weight of500 g/mol or 15 PEG sequences long). It is generated by the reaction ofthe tetra-hydroxyl terminated polyethylene glycol and acryloyl in thepresence of a tertiary amine.

The third component is a peptide binding sequence 2350 with apolyethylene glycol functionality. The polyethylene glycol spacer 2370must be longer then the spacer functionality of the other two componentsto prevent steric hindrance of the matrix components and ensurebio-availability of the peptide binding sequence. In this mixture ofthese three components, the average functionality must be two or greaterto ensure desired gel formation.

In order to use this component system for the treatment of an MI, analiquot of acryloyl functionalities are diluted in water preferably witha basic pH. Then the aliquot is added to a syringe that feed a bore of adual-bore needle (described previously). The thiol component is thenadded to a syringe that controls the second bore of the dual boresyringe. The two components with acryloyl functionalities and thiolfunctionalities are added simultaneously to the infarct region via thedual bore system or via a catheter. The components come in contact withone another at the site and form a gel network with a high oxygencarrying capability.

Example 2

Example 2 incorporates all of the components of Example 1 with anadditional component. Adult skin cells capable of differentiating intocardiomyocytes are added to the second component, a perfluoronatedcompound. The cells may be injected along with the perfluoronated thiol.This would result in the formation of a hydrogel capable of supportingthe oxygen demands of the cell. In addition the gel would swell bytaking up fluids, provide nutrients for the cells and is capable ofeliminating cellular wastes as well as serving as a cellular scaffoldfor deposition of the fibroblasts. Other sources of cells that could bedelivered and survive may include but are not limited to adult, fetaland embryonic stems cells (eg meschenchymal, skeletal myoblast cellsetc.).

Example 3

illustrates the use of gel introduction to the infarct region of adeceased rat heart. Ex-vivo rat hearts were obtained and the hearts weremapped for the infarct region. Less than 30 microliters of material wereinjected into the infarct region. An agent 10% poly(allyl amine)hydrochloride 3.1 grams plus 35% poly(acrylic acid) 0.7 grams system isprotonated, resulting in a stable aqueous solution was maintained at pH3.0 within the catheter until it reached the targeted area. The solutionwas injected into 10% gelatin gel in phosphate-buffered saline. Theinjectate gels instantly. The same injectate was used on the ex-vivo ratheart. The injectate gelled instantly at the infarct region.

Example 4

Sprague-Dawley rats were infarcted by an open chest procedure, ligatureon LAD. Survived for 7 days to allow scar formation, then sacrificed.(Charles River Labs) Hearts removed and packed in ice cold PBS.

The hearts were injected in infarct region by a 1 cc syringe, 30-gaugeneedle. The following polymers were used in the infarct region.

1. PLGA (poly lactic co-glycolic acid polymer, Birmingham Polymers), a20% solution in Diglyme, with 0.6% Sudan Red B was introduced. It wasinjected into infarcted wall. The tissue swells immediately and then thesolution precipitates in the infarct region.

2. Poly(butyl methacrylate co-methyl methacrylate. Mr=100,000 daltons(Aldrich), a 20% solution in Diglyme, with 1% Fat Brown RR. It wasinjected into infarcted wall. The tissue swells immediately and then thesolution precipitates in the infarct region.

3. A 3.1 gram aliquot of a 10% solution of Poly allyl amine (Aldrich)was mixed with 0.7 grams of 35% Poly(acrylic acid) in water (Aldrich).In addition, 1% Toluidine blue was added to the solution. Thiscomposition was injected into infarcted wall. The tissue swellsimmediately and the solution precipitates.

Histology sections (10 micron sliced) demonstrated that the dyedpolymers precipitated within the infarct tissue in the infarct region.

The invention claimed is:
 1. A method comprising: delivering at leastone structurally reinforcing agent through multiple injections to aninfarct region of a ventricle, wherein the structurally reinforcementagent is capable of cross-linking collagen in the infarct region andcomprises at least one of the group consisting of polyepoxy functionalresins, poly-isocyanates, aromatic halogenated compounds,resorcinol-formaldehyde resins, acrylate-terminated materials, lysyloxidase or functionalized microparticles.
 2. The method of claim 1,wherein the delivery of at least one structurally reinforcing agentoccurs within two weeks of a myocardial infarction (MI).
 3. The methodof claim 1, wherein the structurally reinforcing agent is capable ofpreventing thinning of the ventricle.
 4. The method of claim 1, furthercomprising delivering a treatment agent.
 5. The method of claim 4,wherein said treatment agent comprises at least one of the groupconsisting of angiogenic factors, ACE inhibitors, angiotensin receptorblockers, SRCA pump inducers, phospholamban inhibitors andanti-apoptotic agents.
 6. The method of claim 4, wherein the treatmentagent comprises at least one of the following consisting of a smallmolecule, a peptide, a protein or a gene.
 7. The method of claim 6,wherein said treatment agent comprises at least one of the followingproteins consisting of a protein containing an RGD-motif (Arg-Gly-Asp),von Willebrand factor, osteopoetin, fibronectin, fibrinogen,vitronectin, laminin and collagen.
 8. The method of claim 4, whereindelivering the structurally reinforcing agent comprises introducing thestructurally reinforcing agent to the ventricle through a minimallyinvasive procedure.
 9. The method of claim 8, wherein the minimallyinvasive procedure is a sub-xiphoid procedure or a percutaneousprocedure.
 10. A kit comprising: a delivery lumen; and an amount of astructurally reinforcing agent in a biocompatible water miscible solventoperable to be delivered from the delivery lumen, wherein thestructurally reinforcing agent is capable of cross-linking collagen in aventricle and is selected from at least one of the group consisting ofpolyepoxy functional resins, poly-isocyanates, aromatic halogenatedcompounds, resorcinol-formaldehyde resins, acrylate-terminatedmaterials, lysyl oxidase or functionalized microparticles.
 11. The kitof claim 10, further comprising a delivery device.